[FE] String update: When inviting a member to a group, member's role should always be what is set at the invite

When inviting a member to a group and setting the role, effective role of the member is going to be what is set at the invite time. Not the max of the role of the group where the member was.

This maybe just a UX bug - but let's verify functionally that effective role is what is set at invite time (unionized with whatever is set at parents above i.e. AuthZ truism).

This was how group invites worked but we may be changing that too https://gitlab.com/gitlab-org/gitlab/-/issues/577207

The below is the bug - a regression. It should not have the concept of a max role - but instead just give the option to select a role at invite time that applies

This recently broke and started behaving like how group invites work (which is also being discussed if we should break its current behavior)