Context

We currently have two separate methods to generate vector search aggregation pipelines for use in our AI frameworks: vector_search_stage and autoembedding_vector_search_stage. Both generate similar pipelines, the only difference being that one is for auto-embedded vector search indexes and one is for externally-embedded indexes. That difference is not large enough to require two separate methods.

Definition of done

Combine vector_search_stage and autoembedding_vector_search_stage into a single updated vector_search_stage function that serves both types of search pipeline.

Pitfalls

All existing usages of both functions must continue to work unchanged.