Currently, in the event of a an aggregation with a $lookup on the main collection (i.e., a self $lookup), QueryPlannerParams::fillOutSecondaryCollectionsPlannerParams regenerates CollectionInfo, to be stored in secondaryCollectionsInfo.

This is wasteful, and leads to two versions of the same data, which could potentially become inconsistent.

This should be simplified, so that there is a single, canonical place to find collection info for the main colleciton.