[BUGFIX] Use real BE user for logging user setting changes

When editing someone else's user settings as admin the log
should still show the editing user as responsible for the changes.

Resolves: #80947
Releases: master, 8.7, 7.6
Change-Id: I4d57826d65ae34325bea9efdfbd076e47fff0d6d
Reviewed-on: https://review.typo3.org/52548


Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>