MASA 2TC 13.2 and 16.4 DTX to EXT out is broken

Basic info

• Commit SHA: b5bfd17c
• Platform: All

Bug description

Seems that there is a wrong if step in ivas_masa_prerender which causes DTX operation to not copy mono transport to stereo when MASA operates in "stereo as mono" mode and EXT output is selected. The condition is below

    if ( st_ivas->ivas_format == MASA_FORMAT && st_ivas->nchan_transport == 2 && st_ivas->hDecoderConfig->ivas_total_brate < MASA_STEREO_MIN_BITRATE && st_ivas->hDecoderConfig->ivas_total_brate > IVAS_SID_5k2 )

As simple fix is to not use SID-bitrate limitation here.

Ways to reproduce

Encode with DTX, decode to EXT, process with external renderer. This also pops up in valgrind or memory sanitiser for decoder.