Assert in check_ind_list_limits for SBA at 384kbps+

SBA at 384 and 512 apparently hits the limit of indices in our sanitizer tests for 384 and 512 kbps, e.g.: https://forge.3gpp.org/rep/ivas-codec-pc/ivas-codec/-/jobs/92163.

Same thing happened for MASA already, see #502 (closed). As done there, an analysis with a lot of test signals is needed to find a sensible default. PlanarSBA seems fine in this particular case, but should ideally also be checked.