Can't edit and save group permissions because an owner of a revision is no longer exists

Here is also a patch from the MR!

I am not sure it is good idea to assign everything to user 1, as you know on our websites we don't have super user it is just removed

@LOBsTerr The same approach is being used by the group module itself.
On the EC websites, user 1 is exist but blocked. At least for the websites I am working on :). We never deleted user 1!

I've tested the patch with success.

It is similar with the code existing in the module group except that:

1. it applies the change of owner to all revisions and
2. validates the entity before saving (otherwise it would raise an error)

Thank you for your contribution

Automatically closed - issue fixed for 2 weeks with no activity.