Run Blazor E2E tests on Microsoft.Extensions.Validation changes

[oroztocil]

Blazor form validation depends on src/Validation (Microsoft.Extensions.Validation): the DataAnnotationsValidator routes through MEV's IValidatableTypeInfo when a model is registered, and the Blazor E2E suite exercises this via AddValidationIntegrationTest.

However, the list of path triggers for the aspnetcore-components-e2e pipeline did not include src/Validation, so PRs that change only the validation source generator or library never ran the Blazor E2E tests. This let #67636 merge a MEV generator change that broke AddValidationIntegrationTest.FormWithNestedValidation_Works without any signal on the PR.

This adds src/Validation/* to the pr.paths.include filter of both the public and internal components-e2e pipeline definitions, so validation changes now trigger the Blazor E2E tests that depend on MEV.

Related to #67699

[Copilot]

Pull request overview

Updates the Azure DevOps PR path filters for the Blazor Components E2E pipelines so that changes to Microsoft.Extensions.Validation (src/Validation) also trigger the aspnetcore-components-e2e test runs, ensuring validation-related regressions are caught by the Blazor E2E suite.

Changes:

• Add src/Validation/* to pr.paths.include for the public Components E2E pipeline.
• Add src/Validation/* to pr.paths.include for the internal Components E2E pipeline.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
.azure/pipelines/components-e2e-tests.yml	Extends PR path filters to run Components E2E when src/Validation changes.
.azure/pipelines/components-e2e-tests-internal.yml	Mirrors the same src/Validation PR path filter addition for the internal pipeline.

[oroztocil]

@javiercn @Youssef1313 Do you think it is worth it to make CI longer for MEV changes? Alternatively, we could add a simple Blazor app for E2E testing under ./src/Validation/test. (Currently it has only a Minimal API app.)