Description of problem:
This is a follow-up on OCPBUGS-2579, where Prabhu fixed a similar issue for catalog items "Helm Charts" and "Samples" and a follow-up on OCPBUGS-4012 where Jai fied this for Serverless actions "Event Sink", "Event Source", "Channel" and "Broken".

But one "Event source" leftover is still shown when drag and drop the arrow from a Knative Service.

Version-Release number of selected component (if applicable):
4.13, earlier versions have the same issue

How reproducible:
Always

Steps to Reproduce:
1. Install Serverless operator and create Eventing and Serving resources
2. Import an application (Developer perspective > add > container image) and create a Knative Service
3. Open customization (path /cluster-configuration/) and disable all add actions
4. Wait some seconds and check that the Developer perspective > Add page shows no items
5. Navigate to topology perspective and drag and drop the arrow from a Knative Service to an empty area.

Actual results:
"Event Source" is shown

Expected results:
"Event Source" should not be shown

Additional info:
Follow up on OCPBUGS-2579 and OCPBUGS-4012