Fix Spurious Hearing Aid Start and Stop Cmds

Prevent the spurious Start and Stop Commands that are send to the
Hearing Aids when there is audio suspend and resume, and also connection
and disconnections.
Also, make sure that the callback for the Audio Suspend and Resume are
done in the main thread; previously, it was running in the wrong socket
thread.
Lastly, make sure that the Connection Update callback are processed
correctly; previously, we are not checking that the right connection
interval are set and taking the callbacks done by service discovery.

Test: Manual testing with Hearing Aids
Bug: 117619792
Change-Id: I33a175947b0118f0234ec6338c20ac6e7963a598
Merged-In: I33a175947b0118f0234ec6338c20ac6e7963a598
(cherry picked from commit 7d5e6045)