Renderer updates, high MLD fixes

[x] Renderer fixes for dirac dec path
[x] Fix for reverb signal scaling
[x] Stab_fac_fx calculation fix in updt_dec_common

• EVS 26.444 BE test passes.
• decoder pytests:
  MLD scores:
  Original inputs: 562 failed, 374 skipped
  MLD > 10: 4
  MLD > 5 : 54
  MLD < 5 : 504
  +10dB inputs: 562 failed, 374 skipped
  MLD > 10: 89
  MLD > 5 : 177
  MLD < 5 : 296
  -10dB inputs: 562 failed, 374 skipped
  MLD > 10: 2
  MLD > 5 : 11
  MLD < 5 : 549
• encoder pytests results:
  MLD scores:
  Original inputs: 562 tests:
  MLD > 10: 18
  MLD > 5 : 67
  MLD < 5 : 477
  +10dB inputs: 562 tests:
  MLD > 10: 69
  MLD > 5 : 122
  MLD < 5 : 371
  -10dB inputs: 562 tests:
  MLD > 10: 5
  MLD > 5 : 24
  MLD < 5 : 533