[MM-61509] Fix errcheck issues in server/channels/app/user.go (#29154)

Co-authored-by: Ben Schumacher <ben.schumacher@mattermost.com>

server/.golangci.yml

@@ -146,7 +146,6 @@ issues:
         channels/app/team_test.go|\
         channels/app/upload.go|\
         channels/app/upload_test.go|\
-        channels/app/user.go|\
         channels/app/user_test.go|\
         channels/app/web_broadcast_hooks_test.go|\
         channels/app/webhook_test.go|\