Rights are broken when updated automatically upon group deletion: separator becomes pipe instead of comma

Steps to reproduce:

• Delete a group that is used by some rights whose scope includes several groups.

Actual behavior:

• Updated groups are separated by a pipe and the associated right gets broken (e.g. if the right is an allow view right, a user belonging to one of the target groups is not allowed to access the resource).

Excepted behavior:

• Updated groups are separated by a comma and the rights work as expected.