camera: fix flashlight implementation for HAL v2

Update torch availability when the camera device availability changes.

For device HAL v2 and v3 implementation, notify torch unavailable for
all camera devices with a flash unit when a camera device is opened.
Notify torch available for all camera devices with flash unit when
all camera devices are closed.

Don't invoke torch status callback in camera service. Invoke torch
status callback in HAL or FlashControlBase implementations to avoid
race condition.

Clean up previous CL.

Bug: 2682206
Change-Id: I24f5478f467b2c680565fe98f112eef33e2547a1