fix(@angular/build): assert that asset input paths are within workspace root

[alan-agius4]

Ensure that asset patterns defined as objects with an 'input' property are validated to be within the workspace root.

• In '@angular/build', introduce a shared 'isSubDirectory' utility and apply it to both 'normalizeAssetPatterns' and 'resolveAssets'.
• In '@angular-devkit/build-angular', apply similar validation during 'normalizeAssetPatterns'.
• Add integration tests to prevent regressions from absolute and relative path traversal attempts.

[gemini-code-assist]

Code Review

This pull request introduces validation to ensure that asset paths are contained within the workspace root across different Angular builders. It adds a new isSubDirectory utility and implements checks in both the application and browser builders, along with corresponding unit tests. Feedback from the reviewer highlights a potential mismatch in error messages within the new test cases for string-based asset patterns. Additionally, improvements were suggested for the path validation logic to correctly handle edge cases where directory names might start with double dots and to ensure platform-specific path separators are used.

[angular-automatic-lock-bot]

This pull request has been automatically locked due to inactivity.
Please file a new issue if you are encountering a similar or related problem.

Read more about our automatic conversation locking policy.

_{This action has been performed automatically by a bot.}