Camera: Decrease latency when joining sequencer thread

Depending on timing, legacy camera clients that try to
disconnect may observe a random delay while waiting
for the capture sequencer thread to exit from its
respective 'threadLoop'. The delay there can be as much as
'kWaitDuration'.
To improve the average disconnect latency use a separate
and much smaller timeout when managing idle state.

Bug: 143557484
Test: atest cts/tests/camera/src/android/hardware/cts/

Change-Id: I164b3d37182cac776c0064047a5ef5b5a0f8b314