JBM: wrong offset into transport channel buffers in some cases in the main JBM rendering function

The JBM path stores the transport channels in a dedicated buffer and should access those buffers dependent on the number of already rendered samples in the main JBM rendering function. For a few path within the main rendering function this is not done but the rendering is done using always the start of the buffers, leading to wrong output. E.g. in https://forge.3gpp.org/rep/ivas-codec-pc/ivas-codec/-/blob/main/lib_dec/ivas_jbm_dec.c#L704 or https://forge.3gpp.org/rep/ivas-codec-pc/ivas-codec/-/blob/main/lib_dec/ivas_jbm_dec.c#L838

Decoding e.g. a MC bitstream with LFE content and in MCT mode to BINAURAL

(Clear steps or refer to a failing automated test, e.g. with a pipeline link)