To achieve read new for {T324907}, the CheckUser tables now store log events in the structured `log_params` format along with a `log_action` and `log_type`. This means that the action text is generated on the fly when showing results of a check.
When reading old, the action text was generated at insert time. This meant that to allow log entries to be shown that have an entry in `wgLogRestrictions` CheckUser needed to in a `newExtraneousContext` give temporary user rights such that the CheckUser code could save the actiontext to the database. Extensions that were sending log entries would add the rights to `wgCheckUserLogAdditionalRights` such that CheckUser could save the actiontext reliably.
The difference means that the config `wgCheckUserLogAdditionalRights` should no longer be needed, as the action text is generated on view of the log entry and also in a way that uses the rights of the viewing user.
As such, this config should be removed from code in places other than #CheckUser in preparation for it's eventual removal in the parent task T366546.
======Acceptance criteria
* [] Remove modifications or uses of `wgCheckUserLogAdditionalRights` in all code other than in #CheckUser