Camera: Enable external camera handling in default provider.

* The sCameraDeviceStatusChange() callback might be fired between
  initialize() and setCallback(), which can be easily triggered if there
  is an external camera connected at the boot time.

* The external cameras need to be excluded in the getCameraIdList().

Bug: 77833131
Bug: 122800852
Test: Reboot with an external camera is connected, and see the
      camera list is corrected probed in
      $ android-sh -c 'dumpsys media.camera'
      The testing device is Nautilus (Samsung Chromebook Plus).

Change-Id: I5cec6732ce4e26632f1bb5186331b7ce7a94a0b3