[ENG-8016] Re-adding the same user to preprint providers as moderator/admin creates duplicate records.

[antkryt]

Purpose

don't add multiple group perms for preprint provider

Changes

• check if user already belongs to some provider group
• change checkbox to radio select

QA Notes

Documentation

Side Effects

Ticket

https://openscience.atlassian.net/browse/ENG-8016