Deal with MicadoCoroObsFpmBgVirtual template
MicadoCoroObsFpmBgVirtual is just MicadoCoroObsFpm but the background observation of that. This is modeled as a separate template but it is not.
Perhaps we should show this in the documentation as MICADO_coro_obs_fpm[bg]
or so to indicate that it is not the normal data of that template, but also not truly a different template.