Free tier users trying to use a second domain should get a user friendly error

[alex-bezek]

What happened

On the free tier you get 1 domain you can reserve. If you create a new ingress object with a new hostname you can't reserve a new domain but the error isn't clear.

What you think should happen instead

There should be a clear message about reaching a limit on reserved domains and suggested remediations.

How to reproduce

No response