Add foldables posture based closed device state feature flag

Creates a feature flag to update device state provider to
use hall sensor event to unfold device more frequently
based on device posture.

Bug: 309792734
Test: presubmit
Flag: ACONFIG enable_foldables_posture_based_closed_state DISABLED
Change-Id: If6a23e7f79b555d555215c858adb515feb8ac8a3