Assert in encoder in bw_detect_fx for OMASA LTV input (0 dB)
# Basic info
<!--- Add commit SHA used to reproduce -->
- Float reference:
- Encoder (float):
- Decoder (float):
- Fixed point:
- Encoder (fixed): 028d6837bd6d57fb08f26f92f6678327f74eb3c0
- Decoder (fixed):
# Bug description
There is a crash in previously disabled OMASA LTV input case. This is rate switching but encoder config says that current and last bitrate both are 16.4 kbps. This might be related to issue #2141 as the assert happens on fixed path of that. Case happens in this job https://forge.3gpp.org/rep/sa4/audio/ivas-basop/-/jobs/621169

# Ways to reproduce
<!-- Commandline or script -->
```bash
./IVAS_cod -ism_masa 1 2 ltv48_OMASA_1ISM_2TC_ISM1.csv ltv48_OMASA_1ISM_2TC.met ./scripts/switchPaths/sw_13k2_512k_2fr_start_24k4_omasatechs_1ism.bin 48 ltv48_OMASA_1ISM_2TC.wav debug.bit
```
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issue