Update build workflow to include conditional check for image variants

.github/workflows/build.yml

@@ -24,6 +24,7 @@ jobs:
     name: Setup, Build
     runs-on: ubuntu-latest
     continue-on-error: true
+    if : ${{ needs.detect-changes.outputs.image_variants != '[]' }}
     strategy:
         max-parallel: 6
         # select a core set of images to build
@@ -38,7 +39,6 @@ jobs:
 
       - name: Build
         uses: docker/build-push-action@v5
-        if: ${{ matrix.IMAGE_VARIANT }} != '[]' && ${{ matrix.IMAGE_VARIANT }} != ''
         with:
           context: .
           file: ${{ matrix.IMAGE_VARIANT }}