le_audio: Limit possible scenarios to test for device tests

Patch limist scenarios for testing to only matching for required amount
of devices and ASEs.

Test: atest bluetooth_le_audio_client_test
Sponsor: @jpawlowski
Bug: 229802353
Change-Id: I009dadc994a28354460e1d16a027d092fa0eb527
(cherry picked from commit b5938e67d50a88eba6de5b3efb30509739873ecf)