Ignore incoming A2DP if profile is disabled

If profile was disabled (PRIORITY_OFF), it should not accept
incoming connections. A2DP source currently respects priority off, in
A2dpService.isOkToConnect(), but A2DP sink silently accepts incoming
connection.

Bug: 140590407
Test: connect phone with Automotive OS (it implements sink
profile). Disable A2DP from settings in Automotive OS, try to
connect from the phone side - verify A2DP remains disconnected.

Change-Id: I2c385f098ba5dca7ba3d51c2855ed8b22989a15c