$rankFusion has its own extractAndValidateWeights method, which does everything regarding extracting and validating the weights object that we would like to do in $scoreFusion (like weights typo suggestion).

Factor this out into the document_source_hybrid_scoring_util.cpp/h file for reuse in $scoreFusion.

This logic is currently tied to a RankFusionSpec, so some rethinking of what the arguments to the shared utility function should be must be done. Fundamentally, both $rankFusion and $scoreFusion have named input pipelines and named weights arguments that need to be matched up, so some layer of commonality is possible. We may even want to consider commonizing a substructure in IDL between the RankFusionSpec and ScoreFusionSpec to pass into these utility functions.