HFP: Report AT+BIA command to upper layer

* Report AT+BIA command, AG indicator activation command, to upper layer
  so that upper layer can decide on whether or not to subscribe to these
  indicators

Bug: 77655992
Test: make

Change-Id: Ic330d6784c5edf20683cbfedda3fa54525878ce8
(cherry picked from commit 1fa5d797d023576c0d102e2e611345d32daaac42)