build(deps): Bump postcss and @angular-devkit/build-angular (#5248)

Bumps [postcss](https://github.com/postcss/postcss) to 8.5.12 and updates ancestor dependency [@angular-devkit/build-angular](https://github.com/angular/angular-cli). These dependencies need to be updated together.


Updates `postcss` from 8.5.6 to 8.5.12
- [Release notes](https://github.com/postcss/postcss/releases)
- [Changelog](https://github.com/postcss/postcss/blob/main/CHANGELOG.md)
- [Commits](https://github.com/postcss/postcss/compare/8.5.6...8.5.12)

Updates `@angular-devkit/build-angular` from 20.3.16 to 20.3.30
- [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/v20.3.16...v20.3.30)

---
updated-dependencies:
- dependency-name: postcss
  dependency-version: 8.5.12
  dependency-type: indirect
- dependency-name: "@angular-devkit/build-angular"
  dependency-version: 20.3.30
  dependency-type: direct:development
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

package.json

@@ -84,7 +84,7 @@
   },
   "devDependencies": {
     "@alfresco/adf-cli": "9.1.0-28225801456",
-    "@angular-devkit/build-angular": "20.3.16",
+    "@angular-devkit/build-angular": "20.3.30",
     "@angular-devkit/core": "20.3.16",
     "@angular-devkit/schematics": "20.3.16",
     "@angular-eslint/builder": "20.7.0",