MSAN fixes for issues in multichannel and masa formats cases.

EVS 26.444 BE test passes.
pytests results: 588 failed, 381 skipped

MLD scores:
Original inputs:
MLD > 10: 111; Out of these, 51 cases are PLC
MLD > 5 : 124
MLD < 5 : 362

+10dB inputs:
MLD > 10: 221
MLD > 5 : 193
MLD < 5 : 183

-10dB inputs:
MLD > 10: 72
MLD > 5 : 77
MLD < 5 : 448