Bump webpack and @angular-devkit/build-angular in /webapp/frontend

Bumps [webpack](https://github.com/webpack/webpack) to 5.105.2 and updates ancestor dependency [@angular-devkit/build-angular](https://github.com/angular/angular-cli). These dependencies need to be updated together.


Updates `webpack` from 5.76.1 to 5.105.2
- [Release notes](https://github.com/webpack/webpack/releases)
- [Changelog](https://github.com/webpack/webpack/blob/main/CHANGELOG.md)
- [Commits](https://github.com/webpack/webpack/compare/v5.76.1...v5.105.2)

Updates `@angular-devkit/build-angular` from 13.3.11 to 21.2.1
- [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/compare/13.3.11...v21.2.1)

---
updated-dependencies:
- dependency-name: webpack
  dependency-version: 5.105.2
  dependency-type: indirect
- dependency-name: "@angular-devkit/build-angular"
  dependency-version: 21.2.1
  dependency-type: direct:development
...

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

webapp/frontend/package.json

@@ -47,7 +47,7 @@
         "web-animations-js": "^2.3.2"
     },
     "devDependencies": {
-        "@angular-devkit/build-angular": "v13-lts",
+        "@angular-devkit/build-angular": "v21-lts",
         "@angular/cli": "v13-lts",
         "@angular/compiler-cli": "v13-lts",
         "@angular/language-service": "v13-lts",