cameraserver: re-cache concurrent camera id combinations on cameraDeviceStatusChange callbacks.

cameraserver should re-cache concurrent camera id combinations when it
receives cameraDeviceStatusChange callbacks from the camera provider in
case new concurrent camera id combinations have appeared / old ones have
gone away.

Bug: 148995918

Test: atest ConcurrentCameraTest.java

Change-Id: Ic433495d2dcf98d00cb247f434ad6c798ea17c54
Signed-off-by: Jayant Chowdhary <jchowdhary@google.com>