[TASK] Update dependencies and adjust workflows for PHP 8.5

- Remove `ergebnis/composer-normalize` from dev dependencies, it is not compatible with PHP 8.5 yet and not really needed
- Update reusable backport workflow to use the `main` branch.
- Drop support for PHP versions 8.2, 8.3, and 8.4; default to PHP 8.5.
- Modify runTests script and workflow matrix to reflect PHP 8.5 changes.

Author: linawolf

.github/workflows/tests.yml

@@ -34,9 +34,6 @@ jobs:
       - name: Composer validate
         run: Build/Scripts/runTests.sh -p ${{ env.php }} -s composerValidate
 
-      - name: Composer normalize
-        run: Build/Scripts/runTests.sh -p ${{ env.php }} -s composerNormalize -n
-
       - name: CGL
         run: Build/Scripts/runTests.sh -n -p ${{ env.php }} -s cgl -n