[Bug]: ReviewerActionReason has invalid validation rules

[KevinMind]

What happened?

We have loose restrictions on the ReviewActionReason model

But strict restrictions on the admin form. This leads to being able to create reasons via django that are not visible in reviewer tools and or wouldn't pass admin validation.

What did you expect to happen?

We should have consistent validation for the model regardless of where it is created from unless there are special reasons to differ in admin for example. I don't think there are in this case.

~Additionally, there are no default reasons included in our make initialize command meaning any new environment cannot reject versions when a reason is required.~ https://github.com/mozilla/addons/issues/14930

Is there an existing issue for this?

• [X] I have searched the existing issues

┆Issue is synchronized with this Jira Task