Fix quotations

Author: angelapwen

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

@@ -32,6 +32,6 @@ runs:
         echo "version=$VERSION" | tee -a $GITHUB_OUTPUT
 
     - uses: swift-actions/setup-swift@65540b95f51493d65f5e59e97dcef9629ddf11bf # Please update the corresponding SHA in the CLI's CodeQL Action Integration Test.
-      if: runner.os != 'Windows' && steps.get_swift_version.outputs.version != "null"
+      if: runner.os != 'Windows' && steps.get_swift_version.outputs.version != 'null'
       with:
         swift-version: "${{ steps.get_swift_version.outputs.version }}"