ci(aio): include extra files in AIO deployment based on mode

Any files that are inside the `extra-files/{mode}` folder
will be copied over to the `dist` folder before deployment
to Firebase.

See #18287

aio/scripts/deploy-to-firebase.sh

@@ -78,6 +78,9 @@ echo "Deployment URL    : $deployedUrl"
   # Build the app
   yarn build -- --env=$deployEnv
 
+  # Include any mode-specific files
+  cp -rf src/extra-files/$deployEnv/. dist/
+
   # Check payload size
   yarn payload-size