Serdes v2: Improved selective serialization; several fixes for Stats (#25834)

These changes resulted from the effort to serialize and deserialize some
collections from our internal Stats instance, which did not
(de)serialize correctly out of the box.

The main improvement is more robust "escape" analysis - making sure that
all dashboards, cards, models, etc. required by the curated collections
actually belong to those curated collections. (Many cards on Stats were
actually in people's personal collections and publicly readable - that
doesn't work with the curated git workflow.)

This adds some new tests, trying to capture some complex MBQL queries
and make sure they're correctly (de)serialized.