BE-513: HashQL: Rework dynamic aggregate size estimation#8697

indietyp wants to merge 4 commits intobm/be-512-hashql-switchint-allow-cross-backend-transitionshashintel/hash:bm/be-512-hashql-switchint-allow-cross-backend-transitionsfrom

bm/be-513-hashql-size-estimation-aggregate-cardinality-is-wrong-forhashintel/hash:bm/be-513-hashql-size-estimation-aggregate-cardinality-is-wrong-forCopy head branch name to clipboard