Add BluetoothConnectionCallback to Companion App

Tag: #refactor
Fixes: 180729821
Test: atest BluetoothInstrumentationTests
Merged-In: Id24a4b3a3510781d9105763b1722f44583a7fd7c
Change-Id: I598428052191e4a23e4d7cd0b265c84a088431c7
1 file changed