Update config files to prevent duplicated JavaScript tests

[AgentHagu]

What is the purpose of this pull request?

• Documentation update
• Bug fix
• Feature addition or enhancement
• Code maintenance
• DevOps
• Improve developer experience
• Others, please explain:

Overview of changes:
Fixes #2629

As explained in #2629, the core package tests are currently running twice due to having TypeScript and JavaScript versions. To prevent running these tests twice, we can update jest.config.js to only run files that match *.test.ts, thereby ignoring the JavaScript tests.

This PR also updates the tsconfig.json files to further prevent the test.ts files from being compiled to JavaScript in the first place, which also reduces unnecessary output files and keeps the codebase cleaner.

Anything you'd like to highlight/discuss:
As discussed with @gerteck, there shouldn't be a scenario where the TypeScript test passes but the JavaScript version of that test fails -- unless there is an issue during the conversion, which isn't within our scope.

Excluding the test.ts files had an unintended side-effect on ESLint as it previously used tsconfig.json as reference to find TypeScript files to lint. To fix this issue, the PR also adds new tsconfig.lint.json files as the new reference files for .eslintrc.js.

Testing instructions:

1. Navigate to the core package: cd packages/core
2. Run the tests: npm run test
3. Verify that the test report shows 225 total tests, down from the original 445.

Proposed commit message: (wrap lines at 72 characters)
Update config files to prevent duplicated JavaScript tests

The core package tests are currently being run twice because both
TypeScript and JavaScript versions of the test files exist. This leads to
unnecessary duplication of testing, increasing the number of tests
being executed each test run.

To fix this, we update jest.config.js to only run the TypeScript test
files (**/*.test.ts), ignoring the Javascript versions of the tests.

We also update the tsconfig.json files to prevent compilation of
the test.ts files into JavaScript in the first place. This has the added
benefit of reducing the number of unnecessary output files.

A side-effect of excluding the test.ts files in tsconfig.json was that
the ESLint could no longer recognize or find those files for linting. To
fix this, we add tsconfig.lint.json files as the new reference files for
.eslintrc.js

---

Checklist: ☑️

• Updated the documentation for feature additions and enhancements
• Added tests for bug fixes or features
• Linked all related issues
• No unrelated changes

---

Reviewer checklist:

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 51.88%. Comparing base (3aa59b5) to head (7a5e84e).

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #2638   +/-   ##
=======================================
  Coverage   51.88%   51.88%           
=======================================
  Files         127      127           
  Lines        5476     5476           
  Branches     1202     1202           
=======================================
  Hits         2841     2841           
  Misses       2340     2340           
  Partials      295      295           

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[AgentHagu]

Currently waiting for #2637 to be merged first before finalizing this PR.

Finalized PR will remove the need for hardcoding '**/filterIconAssets.test.js' into the testMatch

[gerteck]

Thanks for your effort on this PR! @AgentHagu . This would definitely help immensely with the DevOps process.

One suggestion! - We could also consider excluding the test files from our build pipeline, if it is determined that we don't need the js files at all to run the tests. This can complement the test config, so there are two layers of checks to ensure we don''t run duplicated test files. E.g.:

{
  "extends": "./tsconfig.json",
  "exclude": ["src/**/*.test.ts"]
}

I referenced from stackoverflow

When we add more tests in the future, it can help reduce workload on tsc and also keep our IDE folder less cluttered

[AgentHagu]

One suggestion! - We could also consider excluding the test files from our build pipeline, if it is determined that we don't need the js files at all to run the tests. This can complement the test config, so there are two layers of checks to ensure we don''t run duplicated test files.

Thanks @gerteck for the catch! I've looked into this suggestion and excluding the *.test.ts files in tsconfig.json will indeed compliment the fix. However, there is a small issue with ESLint since it relies on tsconfig.json and packages/core/tsconfig.json to determine which files to lint. Excluding the test files in tsconfig.json would result in ESLint not being able to find those files, leading to errors like:

0:0  error  Parsing error: ESLint was configured to run on <tsconfigRootDir>/packages\core\test\unit\Page\filterIconAssets.test.ts using parserOptions.project:
- <tsconfigRootDir>/tsconfig.json
- <tsconfigRootDir>/packages\core\tsconfig.json
However, none of those TSConfigs include this file.

To resolve this, I've added new tsconfig,lint.json files for ESLint to refer to, ensuring that ESLint can still properly lint the test files while we exclude them from the build pipeline.

[Tim-Siu]

This Pull Request addresses the problems of duplicated JS/TS tests while also enhancing compilation efficiency.

1. It configures Jest to only test TypeScript files.
2. It configures tsconfig so that TypeScript test files are not compiled during the build.
3. The changes in step 2 break linting. This PR creates separate configuration files for linting, adhering to the practices mentioned in this StackOverflow post.

The PR indeed cuts down the test cases run from 462 (commit ea7cf57) to 231 (commit 87616eb). LGTM!

[lhw-1]

Thanks for the PR @AgentHagu! This should've been done after the bulk of the TypeScript migration was completed - so at least we've tied up a loose end.

[github-actions]

@lhw-1 Each PR must have a SEMVER impact label, please remember to label the PR properly.