NIFI-15182: Fixed adding/removing user to multiple groups not saving…

[Freedom9339]

… to all groups.

Summary

NIFI-15182: There was an issue where if multiple groups were selected to add a user to, the update would sometimes fail on all groups, and the operation would have to be repeated to add the user to all desired groups. This also happened when deleting a user from multiple groups. This change fixes this issue.

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  • JDK 21
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