MSAN: use of uninitialized memory in the stereo encoder in ivas-float-update
# Basic info
<!--- Add commit SHA used to reproduce-->
- Float reference:
- Encoder (float):6cf0e3e8c3bfceabfe6ab29598bd3e2a0bed1561
- Decoder (float):6cf0e3e8c3bfceabfe6ab29598bd3e2a0bed1561
# Bug description
With this command line
```bash
./IVAS_cod -stereo 32000 48 scripts/testv/stvST48c.wav bit
```
the memory sanitizer (CLANG=1) reports this error
```
==243029==WARNING: MemorySanitizer: use-of-uninitialized-value
#0 0x5baa2c674d00 in writeLPCparam /home/wkr/ivas-basop/ivas-float-update/lib_enc/enc_prm.c:268:30
#1 0x5baa2c3a2268 in stereo_tcx_core_enc /home/wkr/ivas-basop/ivas-float-update/lib_enc/ivas_tcx_core_enc.c:403:5
#2 0x5baa2c7237c0 in ivas_core_enc /home/wkr/ivas-basop/ivas-float-update/lib_enc/ivas_core_enc.c:256:13
#3 0x5baa2c76874a in ivas_cpe_enc /home/wkr/ivas-basop/ivas-float-update/lib_enc/ivas_cpe_enc.c:742:20
#4 0x5baa2c179ce4 in ivas_enc /home/wkr/ivas-basop/ivas-float-update/lib_enc/ivas_enc.c:178:24
#5 0x5baa2c0c426c in IVAS_ENC_EncodeFrameToSerial /home/wkr/ivas-basop/ivas-float-update/lib_enc/lib_enc.c:1344:24
#6 0x5baa2c0a61c7 in main /home/wkr/ivas-basop/ivas-float-update/apps/encoder.c:788:24
#7 0x7f253d02a1c9 in __libc_start_call_main csu/../sysdeps/nptl/libc_start_call_main.h:58:16
#8 0x7f253d02a28a in __libc_start_main csu/../csu/libc-start.c:360:3
#9 0x5baa2c0075d4 in _start (/home/wkr/ivas-basop/ivas-float-update/IVAS_cod+0x375d4) (BuildId: 3478c6708aa33f74b0ad63edba27f0e375cc1112)
```
Originally fixed in merge request in float repo: https://forge.3gpp.org/rep/ivas-codec-pc/ivas-codec/-/merge_requests/2248
issue