ci: fix approval bypass (#1224)

.github/workflows/build-gateway.yaml

@@ -40,7 +40,7 @@ permissions:
 jobs:
   approve:
     name: approve build release
-    if: ${{ inputs['approval-required'] == true || inputs['approval-required'] == null }}
+    if: ${{ format('{0}', inputs['approval-required']) != 'false' }}
     runs-on: ubuntu-24.04
     environment: builds
     timeout-minutes: 5