Fix thirt party app security exception when call to AudioManager.setMicrophoneMute()

In the current master code, AudioManager.ACTION_MICROPHONE_MUTE_CHANGED
is broadcasted too all users inside setMicrophoneMuteNoCallerCheck().
This causes the third party application needs system permission
android.permission.INTERACT_ACROSS_USERS_FULL or
android.permission.INTERACT_ACROSS_USERS.
Third party application just want to turn on/off microphone but not
about broadcast intent. So we should move broadcast intent code to
AudioService itself.
Therefore, broadcast message to main thread handler to broadcast intent
to avoid security exception.

Bug: 145388173
Test: Write a simple test APP to call to
AudioManager.AudioManager.setMicrophoneMute().

Change-Id: I44cebc9e6e21c1ee0c59125ee702b7093ad38a63