Fixes some of the high MLD cases in Multichannel format test cases

Pipeline results:

• EVS 26.444 BE test passes.
• decoder pytests:
  MLD scores:
  Original inputs: 562 failed, 374 skipped
  MLD > 10: 13
  MLD > 5 : 75
  MLD < 5 : 474
  +10dB inputs: 562 failed, 374 skipped
  MLD > 10: 107
  MLD > 5 : 180
  MLD < 5 : 275
  -10dB inputs: 562 failed, 374 skipped
  MLD > 10: 1
  MLD > 5 : 21
  MLD < 5 : 540
• encoder pytests results:
  MLD scores:
  Original inputs: 562 tests:
  MLD > 10: 18
  MLD > 5 : 71
  MLD < 5 : 473
  +10dB inputs: 562 tests:
  MLD > 10: 66
  MLD > 5 : 124
  MLD < 5 : 372
  -10dB inputs: 562 tests:
  MLD > 10: 5
  MLD > 5 : 30
  MLD < 5 : 527