Domain mapping movement from one service to another is not intutive

Description of problem:

Moving from the domain from one resource to another is not intuitive. The user should be given a warning or message.

Prerequisites (if any, like setup, operators/versions):

Serverless is installed

Steps to Reproduce

1. Create a serverless workload with domain mapping
2. Check the domain mapping details in the workload sidebar
3. Create another workload using same domain mapping
4. Check the domain mapping details on the first workload

Actual results:

Domain mapping is removed from the first workload without any warning

Expected results:

A warning should be provided to the user

Reproducibility (Always/Intermittent/Only Once):

Always

Build Details:

4.9.0-0.nightly-2021-08-29-010334

Additional info: