BigQuery multi table sink assumes that the pipeline has multi table source (context: https://groups.google.com/g/cdap-user/c/FuI7HAEF_z0/m/8jKuPdduAAAJ). However currently its possible to create a pipeline without multi table source and deploy it. Such pipeline preview and actual run fails with error:
"BigQuery Multi Table has no outputs. Please check that the sink calls addOutput at some point."
We should fail the deployment of the pipeline in such case with appropriate error message.
This might require data pipeline app support though in the form of some API so that plugin can specify dependency on other plugins which app can validate during the deployment.