Use Java 21 for spotless and do not force to run on ubuntu

Signed-off-by: rithin-pullela-aws <[email protected]>

.github/workflows/CI-workflow.yml

@@ -23,15 +23,13 @@ jobs:
       product: opensearch
 
   spotless:
-    if: github.repository == 'opensearch-project/ml-commons'
-    runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
       # Spotless requires JDK 17+
-      - uses: actions/setup-java@v4
+      - name: Setup Java 21
+        uses: actions/setup-java@v1
         with:
-          java-version: 17
-          distribution: temurin
+          java-version: 21
       - name: Spotless Check
         run: ./gradlew spotlessCheck