Add RestartPackager command unit tests

[ConnorQi01]

Summary

Add unit coverage for the RestartPackager command.

Proposed Changes

• Cover the successful restart flow after the React Native package version check resolves.
• Cover the failure path where the version check rejects and the packager is not restarted.
• Verify the configured packager port is requested with the project path and forwarded to restart.

Test Plan

• npx prettier --check test\extension\commands\restartPackager.test.ts
• npm run build
• npm test - fails in existing tests: rn-extension commandsRegistered command list assertion, and logCat/android asynchronous channel failure. restartPackagerCommand ran 3 tests with 0 failures.

Closes #2773

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