ci: Skip running compressed-size builds twice

Author: rschristian

.github/workflows/size.yml

@@ -20,3 +20,6 @@ jobs:
       - uses: preactjs/compressed-size-action@v2
         with:
           repo-token: '${{ secrets.GITHUB_TOKEN }}'
+          # Our `prepare` script already builds the app post-install,
+          # building it again would be redundant
+          build-script: 'npm run --if-present noop'