[GH Actions] tackle unmaintained Gradle GH actions

This change replaces the now unmaintained `gradle/gradle-build-action` with `gradle/actions/setup-gradle`.

Also remove the unmaintained `gradle/wrapper-validation-action` w/o a replacement, assuming #36771 is going in.

Author: snazy

.github/actions/setup-environment-action/action.yml

@@ -76,9 +76,10 @@ runs:
         distribution: 'temurin'
         java-version: ${{ inputs.java-version == 'default' && '11' || inputs.java-version }}
     - name: Setup Gradle
-      uses: gradle/gradle-build-action@v2
+      uses: gradle/actions/setup-gradle@4d9f0ba0025fe599b4ebab900eb7f3a1d93ef4c2 # v5
       with:
         cache-disabled: ${{ inputs.disable-cache }}
+        validate-wrappers: false
     - name: Install Go
       if: ${{ inputs.go-version != '' }}
       uses: actions/setup-go@v6

.github/workflows/code_completion_plugin_tests.yml

@@ -68,10 +68,6 @@ jobs:
           repository: JetBrains/intellij-community
           path: intellij
 
-      # Validate wrapper
-      - name: Gradle Wrapper Validation
-        uses: gradle/[email protected]
-
       # Setup Java environment for the next steps
       - name: Setup Java
         uses: actions/setup-java@v5