Button to fix users missing display name and email in their user settings

I will create a fix button in admin settings that will go through and populate the user settings with the appropriate name and email if missing

Start by locating the admin settings and user settings implementations, then trace how user names and email addresses are stored and updated. Confirm the expected source for missing values and verify that the fix button populates only missing fields for the relevant users.

Written by the indexing model from the issue text.