OSBA EXT output wrong for FOA/HOA2 inputs

The OSBA EXT output is wrong: the number of output channels is always 16 (HOA3 channels) + ISM channels regardless of the ambisonics order at the codec input. Thus e.g. OSBA FOA input that is outputted to EXT should have 4 (FOA channels) + ISM channels.

I think that the current (wrong) logic comes from days when the ambisonics order was not always part of the OSBA bitstream and was not corrected later after #1061 (closed) was solved.

Note that TS26.253 mentions the following:

If EXT output is configured a. SBA is rendered to HOA3 (see clauses 6.4.6.5.3 or 6.4.6.5.4) b. Object audio channels are copied from the transport-channel buffer to the output buffer

which is, however, not correct in my view as well. I believe (and see also discussion at https://forge.3gpp.org/rep/ivas-codec-pc/ivas-codec/-/wikis/Meetings/Reports/2024-04-09%20Technical%20Matters) that EXT output corresponds to the so-called pass-through operation which outputs the same number of channels and metadata as were inputted to the codec. So I think that the TS text should be corrected too.

From the first look into the source code, at least the following logic is wrong in ivas_init_dec, line 943:

        else if ( st_ivas->ivas_format == SBA_ISM_FORMAT )
        {
            hDecoderConfig->nchan_out = audioCfg2channels( IVAS_AUDIO_CONFIG_HOA3 ); // should be FOA/HOA2/HOA3 depending on the decoded st_ivas->sba_order parameter
            hDecoderConfig->nchan_out += st_ivas->nchan_ism;
        }

and line 984:

    if ( st_ivas->ivas_format == SBA_ISM_FORMAT && output_config == IVAS_AUDIO_CONFIG_EXTERNAL )
    {
        st_ivas->hOutSetup.ambisonics_order = SBA_HOA3_ORDER;  // should be FOA/HOA2/HOA3
        st_ivas->intern_config = IVAS_AUDIO_CONFIG_HOA3;   // should be FOA/HOA2/HOA3
        st_ivas->hOutSetup.output_config = IVAS_AUDIO_CONFIG_HOA3;   // should be FOA/HOA2/HOA3
        st_ivas->hOutSetup.nchan_out_woLFE = audioCfg2channels( IVAS_AUDIO_CONFIG_HOA3 );  // should be FOA/HOA2/HOA3
    }