DO NOT MERGE: HA still appears in Media device list even though it has been unpaired.

-Add mUnpairing to mark the device triggers removeBond()
-For HA, once it calls removeBond(), two HA would be unpaired. It causes the incorrect state if we do main/sub devices switching.

Bug: 198124571
Test: manual test

Merged-In: I4ed5db2bd01f4b4e8f246ed3e8f74e24149571f9
Change-Id: I4ed5db2bd01f4b4e8f246ed3e8f74e24149571f9
(cherry picked from commit 5597cbd7)