[CI]Add missing rate switching modes for ism ext MD

In scripts/config/ivas_modes.json , the rate switching modes for ISM+X formats were missing. This caused some things to be missing in our automated tests:

• complexity tests did not run rate switchign for ISM, that's why the graphs are empty for that. fyi @vaclav
• the sanitizer pipelines for ISM+ do not run rate switching. This might reveal some so far undiscovered problems as these modes haven't been running due to the missing modes. fyi @mullerfa