[bt-audio] Fix dbus method reply for audio connect

[bt-audio] Fix dbus method reply for audio connect

Application is showing as Connecting and never came back to
Disconnected or Connected state(Application didn't got dbus
reply for audio connect method call)

We were overwriting the global data which stores request id to which
we need to reply. Because of which bt-service will not able to reply
to dbus request. For Ex. Already Headset A is connected, Applications
sends connection request for Headset B, than bt-service initiates
disconnection for Headset A and Stores Headset B in global wait data.
And When Headset A's HFP profile is connected, Application sends
connection request for Headset C, than bt-service initiates disconnection
for Headset B and overwrite the global wait data with that of Headset C.

Measure: Before checking if any device is connected or not check first
if any device is in connecting state with type. If any device is in
connecting state than return IN_PROGRESS error no need to handle.

Change-Id: I1e721f2e2660274ecef2c3cf551377572e557b3b