[regression-merge] Decoder: Loudness difference ivas-float-update vs. float-pc for MC BINAURAL_ROOM_IR + Headrotation output
# Basic info
<!--- Add commit SHA used to reproduce -->
- Float reference (ivas-float-update):
- Encoder (float): c21351165b0cace2fd8686b3935ed074b0f99ba2
- Decoder (float): c21351165b0cace2fd8686b3935ed074b0f99ba2
- Branch float-pc:
- Encoder (fixed): n/a
- Decoder (fixed): aa9a63703e64ce842b6b862e47486fd9066a657a
# Bug description
When decoding the attached bitstream with head-rotation, there is a significant loudness difference between the floating-point decoders in ivas-float-update and float-pc: The decoder from float-pc is significantly louder. The fixed-point decoders (main, main-pc) are loudness-wise inline with ivas-float-update. Also, when we switch off head-rotation, this loudness increment disappears again.
# Ways to reproduce
<!-- Commandline or script -->
```bash
IVAS_dec -t scripts/testv/headrot_case00_3000_q.csv BINAURAL_ROOM_IR 48 stv51MC48c.wav_Multi_channel_5_1_at_64_kbps_48kHz_in_48kHz_out_BINAURAL_ROOM_IR_out_HR.192 out.wav
```
Bitstream: [stv51MC48c.wav_Multi_channel_5_1_at_64_kbps_48kHz_in_48kHz_out_BINAURAL_ROOM_IR_out_HR.zip](/uploads/7f63a6c202349f18a27e4e2bdc6910d7/stv51MC48c.wav_Multi_channel_5_1_at_64_kbps_48kHz_in_48kHz_out_BINAURAL_ROOM_IR_out_HR.zip)
<!--- Below are labels that will be added but are not shown in description. This is a template to help fill them.
Add further information to the first row and remove and add labels as necessary. -->
issue