Preparing the 0.7.3 release

[tnaum-ms]

This pull request documents and prepares the release of version 0.7.3 of the DocumentDB for VS Code extension. It updates the version number, changelogs, and documentation to reflect new features, dependency upgrades, and telemetry improvements.

Release documentation and versioning:

• Bumped the extension version to 0.7.3 in package.json.
• Added a new section for version 0.7.3 in CHANGELOG.md, highlighting the cancellable connection feature, Node.js 22 and dependency upgrades, and telemetry improvements.
• Updated the release notes in docs/release-notes/0.7.md to describe the new features, improvements, and provide links to the relevant changelog entries.
• Updated docs/index.md to include a link to the 0.7.3 release notes.

[Copilot]

Pull request overview

Prepares the DocumentDB for VS Code extension v0.7.3 release by updating versioning and adding/refreshing release documentation so the shipped artifact and published notes align.

Changes:

• Bumped extension version to 0.7.3 in package.json and package-lock.json.
• Added a 0.7.3 entry to CHANGELOG.md covering connection cancellation, Node.js 22/dependency upgrades, and telemetry refinements.
• Updated the 0.7 release notes and docs index to include 0.7.3.

Reviewed changes

Copilot reviewed 4 out of 5 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
package.json	Updates extension version to 0.7.3.
package-lock.json	Keeps lockfile version metadata in sync with 0.7.3.
CHANGELOG.md	Adds 0.7.3 changelog section summarizing key items.
docs/release-notes/0.7.md	Appends 0.7.3 patch release notes with links to PRs/changelog.
docs/index.md	Adds navigation link to 0.7.3 release notes anchor.