test: add 20.0-project E2E test asset and update update tests to use it

[alan-agius4]

Update e2e assets

[gemini-code-assist]

Code Review

This pull request upgrades the E2E test asset project from Angular v19 (nineteen-project) to Angular v20 (twenty-project), updating configuration files, dependencies, and test scripts accordingly. Feedback on the changes highlights two critical issues: first, provideBrowserGlobalErrorListeners is incorrectly imported from @angular/core instead of @angular/platform-browser, which will cause a compilation error; second, the index option is missing from the build configuration in angular.json, which will prevent the generation of the entry HTML file and cause E2E tests to fail.

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[alan-agius4]

This PR was merged into the repository. The changes were merged into the following branches:

• main: 11a4438
• 22.0.x: 282c095