LeAudio/multicodec: Fix the async data path getter API

Just like the returned data path configurations are split for each direction,
the function arguments should also have the directional context. The vendor
module might need to know which connection handles in the stream map are for
the sink and which are for the source direction, to provide the proper
data path configurations for each direction.

Bug: 308428217
Bug: 307258939
Test: m android.hardware.bluetooth.audio-update-api
Change-Id: I270b6f4631869e2180580c886f0b58bd777d2123