le_audio_software: Fix CancelStreamingRequestV2 functions

This part has been ommited in previous fix

commit 124fb75a
    leaudio: Fix possible race on start stream request from HAL

Bug: 322106376
Bug: 325181889
Test: mmm packages/modules/Bluetooth
Test: manual, media/phone call stream
Change-Id: I9b2191312284a7f0a04ec51a7656f028e09a806d