leaudio: Allow unidirectional GAME context.

When remote device supports GAME on only one direction,
stack will respect it.

Bug: 351974325
Bug: 313054645
Test: atest bluetooth_le_audio_client_test bluetooth_le_audio_test
Flag: com.android.bluetooth.flags.leaudio_multicodec_aidl_support

Change-Id: Idd5f9fdd0f645d452e348afd539b20636d84ec61