Resource deletion safety check

[xiaofei-du]

When a user deletes a resource, if there are other resources depending on it, the deletion operation should return an error (status code: 422) with reason.

• pipeline-backend: need to add search or filter endpoints (AIP-160) to support above queries @pinglin
• connector-backend: query pipeline-backend if a connector is being used by any pipeline @pinglin
• model-backend: query pipeline-backend if a model instance is being used by any pipeline @Phelan164

[xiaofei-du]

Resolved.

[linear]

INS-4646 Resource deletion safety check