Traffic Splitting Dialog is Confusing With Only One Revision

Description of problem:

Disabled text, no clear understanding why or how to fix it – nothing to gleam here other than you can't do it.

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

Serverless Operator

Steps to Reproduce

1. Add Knative Service
2. Right Click on it and go to Set traffic distribution

Actual results:

Disabled action items without help or explanation.

Expected results:

Disabled cursor when hovering and a tooltip (even if just browser supported) to why it can't happen. Can't delete, can't add.

Reproducibility (Always/Intermittent/Only Once):

When there is only one Revision on a Knative Service

Build Details:

4.8.0-0.nightly-2021-04-26-151924

Additional info: