1. Add this function to the API

MongoExtensionStatus* (*set_vector_search_limit_for_optimization)(                                const MongoExtensionLogicalStage* logicalStage,                                 long long* extractedLimitVal);

2. Extension must set the limit used in the optimizations to the minimum of the passed limitVal and the $vectorSearch stage's provided limit.
This limit value will be used for the following optimizations:

• The extension $vectorSearch should add a $limit to its DistributedPlanLogic’s merging pipeline
• The extension $vectorSearch can use the limit to compute the numCandidates:limit ratio metric