Camera: Fix missing physical camera availability callback

The missing physical camera availability callback is due to a race
condition between provider enumeration and physical camera availability
callback. If the HAL triggers a physical camera availability callback,
it could be dropped because the logical camera's availability callback
isn't triggered until the provider enumeration finishes.

Fix the issue by deferring physical camera availability callbacks
until the logical camera availability callback is called.

Test: Camera CTS, vendor test on foldable phone, cameraservice_test
Bug: 255472536
Change-Id: Ia5a535b1530b3666e616cc3619fcb759ff5d8560