Bump @angular/cli from 20.3.3 to 21.2.9 in /angular-app

Bumps [@angular/cli](https://github.com/angular/angular-cli) from 20.3.3 to 21.2.9.
- [Release notes](https://github.com/angular/angular-cli/releases)
- [Changelog](https://github.com/angular/angular-cli/blob/main/CHANGELOG.md)
- [Commits](angular/angular-cli@20.3.3...v21.2.9)

---
updated-dependencies:
- dependency-name: "@angular/cli"
  dependency-version: 21.2.7
  dependency-type: direct:development
  update-type: version-update:semver-major
...

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Author: dependabot[bot]