DO NOT MERGE ANYWHERE Allow blocking AG SCO connects by policy

Needed for devices that support both HFP AG and HFP HF.

btsnoop logs show the sequence of events leading to failure:
(corroborated by bt logcat)

1. ACL connection with remote phone established on handle 0x01
2. ACL connection with remote headset established on handle 0x02
3. Incoming call in HF role from phone
4. Phone call locally published to telecom
5. Answer incoming call
6. SCO connection established with phone in HF role
7. AG role with headset picks up on call state change to answered
   via BTA_AG_IN_CALL_CONN_RES
8. Inside handler for BTA_AG_IN_CALL_CONN_RES, bta_ag_sco_open called
   to establish the SCO connection in the AG role with the headset,
   stomping on the previous (wanted) SCO connection with the phone.

Fix is to publish the SCO audio route policy to fluoride, so we can
stop 8 from happening.

Bug: 32958838
Test: manual:
      received incoming call in HF role, audio worked both ways;
      recieved incoming MT call, headset audio in AG role worked both ways
Change-Id: I12961598e8200bd1d5adb46ee8ec3a802114b80a