Revert "Removed explicit wrapper validation, as that's checked by def…

…ault with every setup-gradle action since v4"

This reverts commit 0f7073a.

.github/workflows/gradle-wrapper-validation.yml

@@ -0,0 +1,14 @@
+name: Validate Gradle Wrapper
+
+on: [ push, pull_request, workflow_dispatch ]
+
+jobs:
+  validation:
+    name: Validation
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+      - name: Validate
+        uses: gradle/actions/wrapper-validation@v4
+