Fix FD leak caused by module wrapper thread

Use Case: Repeated BT ON/OFF

Failure: FD leak is observed with ON/OFF stress test
which eventually leads to crash due to unavailability
of FDs.

Steps:
BT ON/OFF.

Root Cause: During cleanup the module wrapper thread is
stopped but the resources are not freed, leading to FD leak.

Fix: Cleanup the module wrapper thread properly so that there
are no resource leaks.

Bug: 28312228
Change-Id: I4de2fba9c98a0e4ae73315759ec6bc8bf273948e