State that a project is in the trash when deleting a permission scheme related to it

Issue Summary

When you move a project to the trash, its relation with permission schemes is still kept as that's something necessary in case you want to restore the project eventually.

But if you try to delete the associated permission scheme it will point out that the project in question is still using the permission scheme, although without saying taht the project is in the trash:

Error message:

The scheme cannot be deleted when there are projects associated with it.

Suggestion

Modify the current messages so they state whether the associated project(s) are in the trash or not, which would make it easier for users to know where to look at.