MM-60926: updated system_test.go to pass linter (#28691)

server/.golangci.yml

@@ -90,7 +90,6 @@ issues:
         channels/api4/status.go|\
         channels/api4/system.go|\
         channels/api4/system_local.go|\
-        channels/api4/system_test.go|\
         channels/api4/team_local.go|\
         channels/api4/team_test.go|\
         channels/api4/user.go|\