Fix syntax in external openhands-resolver.yml (#5453)

openhands/resolver/examples/openhands-resolver.yml

@@ -23,7 +23,7 @@ jobs:
     with:
       macro: ${{ vars.OPENHANDS_MACRO || '@openhands-agent' }}
       max_iterations: ${{ fromJson(vars.OPENHANDS_MAX_ITER || 50) }}
-      base_container_image: ${{ vars.OPENHANDS_BASE_CONTAINER_IMAGE || "" }}
+      base_container_image: ${{ vars.OPENHANDS_BASE_CONTAINER_IMAGE || '' }}
     secrets:
       PAT_TOKEN: ${{ secrets.PAT_TOKEN }}
       PAT_USERNAME: ${{ secrets.PAT_USERNAME }}