User Model Policy 被覆蓋

加入Impersonation後無法使用UserPolicy進行權限控管，推測原因為ImpersonationServiceProvider->registerPolicy直接將ImpersonationPolicy綁到User Model上。

@chensiyu 有空檢查看看？

mentioned in merge request !3 (merged)

mentioned in commit 60c3d2f2

closed with merge request !3 (merged)