Remove HAL endpoint callback thread

The extra thread can be removed because the HAL callback interface is oneway. This CL also modifies the notePermission call to be done with a clean binder identity to avoid permission issues.

Bug: 388607517
Flag: android.chre.flags.offload_implementation
Test: CHQTS endpoint test pass

Change-Id: I20d98a6337c80f0e9e6c4ac58a42907191736ee9