Resolve separate binding for BT ICS.

Improve the work that was done as part of the call audio refactoring
work to separately bind to the BT ICS. This involves ensuring that the
BT ICS is bound to prior to the Dialer ICS, namely, for handling MT
calls. This will allow the BT call audio to properly handle ringing as
well as the disconnect tone for SCO.

This CL also modifies the new call audio routing logic to ensure that
the call audio route is properly updated to bluetooth when the SCO audio
is connected. It is possible that the headset state isn't updated when
Telecom tries to connect to the SCO device, resulting in Telecom
receiving an indication that the connection failed. Once the headset
state is updated, the SCO audio will be connected and the audio will be
routed to the device. Telecom should ensure that the UI is properly
routed to reflect this. This does open up other possible race conditions
like if an app requests audio to be routed to BT and Telecom requests
SPEAKER_ON shortly after; if the SPEAKER_ON message is processed first,
then the audio will be routed to BT instead if BT_AUDIO_CONNECTED is
received after. This issue is difficult to resolve since if we ignore
the BT_AUDIO_CONNECTED message when we don't expect a pending route
switch, it opens ourselves to the aforementioned issue of the UI not
reflecting that the audio has been routed to BT, which I think is a more
prominent issue. This would probably require further discussion and
possibly help from the BT team to help provide relevant information to
the receiver which Telecom could use to decide when to ignore the
connection state change.

Bug: 328287261
Test: atest TelecomUnitTests
Test: atest CtsTelecomTestCases
Test: Manual to ensure disconnect tone is heard via HFP headset and
verified logs to make sure that BT ICS is bound before Dialer ICS.
Test: Manual toggling BT on/off in personal/work profile to ensure BT
ICS is bound.

Change-Id: I676159ad85edb962b2c7a1c782c8edd065e9c144