Disable Delete button for Patron Group that is in use by one or more users

Purpose:
To disable the deletion of a patron group that is in use by one or more users, and add hover text explaining why it is disabled

Scenarios:

1. Scenario

   • Given the Delete button/icon on Settings > Users > Patron groups

   • When the group is in use by one or more users

   • Then the Delete button will be disabled

2. Scenario

   • Given the disabled Delete button on Settings > Users > Patron group

   • When hovered over

   • Then hover text will appear: "Patron group cannot be deleted when used by one or more users"

3. Scenario

   • Given the disabled Delete button on Settings > Users > Patron group

   • When clicked

   • No deletion will occur and hover text will appear: "Patron group cannot be deleted when used by one or more users"

NOTE: has the overall requirements for the new appearance for this page and it is still in progress and has some open questions. Even still, we should probably just do this, as the current delete behavior for this page is buggy.