Decoder crash for Stereo at 48/64 kbps mono decoding in IMDCT_ivas_fx()
# Basic info
<!--- Add commit SHA used to reproduce -->
- Float reference:
- Encoder (float): e15ad0addc0b0a429fcf05e1683e77c05164738a
- Decoder (float):
- Fixed point:
- Encoder (fixed):
- Decoder (fixed): d4fd91a6c
# Bug description
The decoder crashes with an assert:
{width=309 height=351}
# Ways to reproduce
Box folder: ...\Box_EXTERNAL_IVAS_BASOP_VERIFICATION\issues\issue-1342
<!-- Commandline or script -->
```bash
./IVAS_cod_flt_ref -stereo -max_band FB 48000 48 am1aa1s07_48.10dB.wav bit
./IVAS_dec_fx mono 48 bit out.wav
```
The crash also occurs for 64kbps for decoding to any output sampling rate (16/32/48). Also occurs conditions if the uploaded error pattern is applied:
```
eid-xor -vbr -fer bit stereo-mixed-music.am1aa1s07_ep.192 bit_err
```
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issue