leaudio: set preferred codec config conv test part 2

Adding unit test for api:SetCodecConfigPreference for all use cases
during conv streaming

Bug: 259191520
Bug: 353909820
Flag: TEST_ONLY
Test: atest bluetooth_le_audio_test bluetooth_le_audio_client_test
Change-Id: Iab2c6d4c8b5e18b7b6369e63624146cd24eaf7eb