When trying to deploy ADK Agents with GCS Artifact via ADK CLI. The given custom adk_app.py is not transferred to the temporary folder and the default app is always created. Causing not able to deploy with custom services.

On inspection of ADK CLI deploy.py file, it doesn't seem to check whether the custom adk app file exists or not it just creates a default app irrespective with the default settings(No additional services).

Please fix this bug by adding a condition to check whether custom app file exists.

Even better will be to easily change Needed services via CLI itself.