Switch ERI_MSVQ_CLEANUP can cause crashes in ISM DTX

With ERI_MSVQ_CLEANUP being active, there is a crash in ISM2 DTX encoding with the longer testvector signals:

Assertion failed: (N == FDCNG_VQ_MAX_LEN || N == FDCNG_VQ_MAX_LEN_WB), function msvq_enc, file lib_enc/lsf_msvq_ma_enc.c, line 469.

Reproduce with either

python3.10 ./scripts/runIvasCodec.py -p ci_linux_ltv.json -m ISM2_b16_4_dtx_wb_cbr

or resample the ltv48_2ISM.wav testvector to 16kHz and run

./IVAS_cod -dtx -ism 2 NULL NULL -max_band wb 16400 16 ltv48_2ISM_16_ISM2.pcm bit