Bump webpack-dev-server and @angular-devkit/build-angular in /manager2

Removes [webpack-dev-server](https://github.com/webpack/webpack-dev-server). It's no longer used after updating ancestor dependency [@angular-devkit/build-angular](https://github.com/angular/angular-cli). These dependencies need to be updated together.


Removes `webpack-dev-server`

Updates `@angular-devkit/build-angular` from 0.1002.1 to 21.2.16
- [Release notes](https://github.com/angular/angular-cli/releases)
- [Changelog](https://github.com/angular/angular-cli/blob/main/CHANGELOG.md)
- [Commits](https://github.com/angular/angular-cli/commits/v21.2.16)

---
updated-dependencies:
- dependency-name: webpack-dev-server
  dependency-version:
  dependency-type: indirect
- dependency-name: "@angular-devkit/build-angular"
  dependency-version: 21.2.16
  dependency-type: direct:development
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]