assert in the encoder coming from a missing saturation
# Basic info
<!--- Add commit SHA used to reproduce -->
- Fixed point:
- Encoder (fixed): 20cb1008
# Bug description
Assert cause by a missing saturation.
```
> IVAS_cod.exe!L_add Line 1681 C
IVAS_cod.exe!gauss2v_ivas_fx Line 984 C
IVAS_cod.exe!gaus_encode_ivas_fx Line 181 C
IVAS_cod.exe!encod_unvoiced_ivas_fx Line 332 C
IVAS_cod.exe!acelp_core_enc_ivas_fx Line 1520 C
IVAS_cod.exe!ivas_core_enc_fx Line 358 C
IVAS_cod.exe!ivas_cpe_enc_fx Line 1285 C
IVAS_cod.exe!ivas_enc_fx Line 185 C
````
# Ways to reproduce
<!-- Commandline or script -->
```bash
ivas_cod -STEREO 2 32000 48 ltv48s.wav bit
```
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issue