ASAN: Memory leak in LTV sanitizer test for EVS encoder
# Basic info
<!--- Add commit SHA used to reproduce-->
- Encoder (fixed): a51ce5c2ef07dc1ebe69c8d86a4f7d22965e86b6
# Bug description
In our long test vector sanitizer job, EVS and Stereo downmix to EVS modes show a memory leak:
```
=================================================================
==20877==ERROR: LeakSanitizer: detected memory leaks
Direct leak of 960 byte(s) in 1 object(s) allocated from:
#0 0x49c26d in __interceptor_malloc (/builds/rep/sa4/audio/ivas-basop/IVAS_cod+0x49c26d)
#1 0xb39826 in init_encoder_fx /builds/rep/sa4/audio/ivas-basop/lib_enc/init_enc_fx.c:368:55
#2 0x705bf9 in create_evs_sce_enc_fx /builds/rep/sa4/audio/ivas-basop/lib_enc/ivas_sce_enc_fx.c:562:5
#3 0x5bbd37 in ivas_init_encoder_fx /builds/rep/sa4/audio/ivas-basop/lib_enc/ivas_init_enc_fx.c:569:9
#4 0x4e0dbb in configureEncoder /builds/rep/sa4/audio/ivas-basop/lib_enc/lib_enc_fx.c:1146:5
#5 0x4ddecf in IVAS_ENC_ConfigureForMono /builds/rep/sa4/audio/ivas-basop/lib_enc/lib_enc_fx.c:312:13
#6 0x4cfe48 in main /builds/rep/sa4/audio/ivas-basop/apps/encoder.c:388:28
#7 0x7f9a889abd8f in __libc_start_call_main csu/../sysdeps/nptl/libc_start_call_main.h:58:16
SUMMARY: AddressSanitizer: 960 byte(s) leaked in 1 allocation(s).
```
https://forge.3gpp.org/rep/sa4/audio/ivas-basop/-/jobs/541131
# Ways to reproduce
<!--Commandline or script-->
```bash
IVAS_cod 64000 48 ltv48_MONO.wav bit1
IVAS_cod -stereo_dmx_evs 13200 32 ltv32_STEREO.wav bit2
```
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issue