cameraserver: remove assumption that status change callbacks must be called...

cameraserver: remove assumption that status change callbacks must be called from cameraserver process.

Some code in disconnectClient, which is probably a remnant from pre-treble days assumes
onDeviceStatusChanged callbacks can be made from only the cameraserver process.
Post treble, this is not true since the cameraserver could receive a cameraDeviceStatusChanged
callback from the camera HAL process (which could call onDeviceStatusChanged).

Bug: 158252149

Test: GCA (sanity)

Change-Id: Ic76ecf45b0c06dcb69d1b0758b7cd9047a0364ac
Signed-off-by: Jayant Chowdhary <jchowdhary@google.com>