Add a lock to protect mRunningUids in GenericWindowPolicyController

- Open the camera on the virtual display and immediately use
  CameraAccessController's isAppRunningOnAnyVirtualDevice to judge, it
  may cause race conditions in onRunningAppsChanged() and containsUid(),
  making the result incorrect.

Bug: 218400882
Test: Manual
Change-Id: I61fc436da96b007614db2c8f0a10cf060462138c