Site form validation for permission groups doesn't work

Summary

It seems that - with the current develop branch - the validation for permission groups doesn't work when we try to add / edit sites. It is possible to add them without any permission group.

Steps to reproduce

• empty db
• new site page
• insert label
• don't add a permission group
• stay with the default visibility (internal)
• click on create

What is the current bug behavior?

The creation just runs. There is no validation that stops the user from adding a site without permission groups.

What is the expected correct behavior?

There should be an error message that forces the user to add at least one permission group to the site.

Some logs and/or screenshots

Possible fixes

Not completely sure, but in the current master branch the validation works. This was before I asked Tim to change the error message (that pointed to the private state - which is not possible for sites).

ToDo's

• Bug reproduced
• Cause found
• Bug fixed