Unable to autofill for parts with multiple engine configs / multiple subconfigs on different parts

[Capkirk123]

If a part has multiple engine configs with unique fuel requirements, for example (primary and potentially only) the RO KTDU-417, the tank autofill feature will only appear for the first config defined in the MM cache.

I suspect KSP-RO/RealismOverhaul#2796 is related, in which when different subconfigs of the same config are selected, only the part which was placed first can be autofilled.