SQL Server: Implement support for VECTOR_SEARCH()

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#36383 is adding support for the new SQL Server vector data type, as well as the translation of VECTOR_DISTANCE(), which performs precise, slow (non-index-driven) similarity search. In contrast, [VECTOR_SEARCH())(https://learn.microsoft.com/en-us/sql/t-sql/functions/vector-search-transact-sql?view=sql-server-ver17) allows approximate, index-driven search.

VECTOR_SEARCH() seems to be in a more experimental stage at this point, and its design as a special TVF (as opposed to VECTOR_DISTANCE() which is just a regular scalar function) both makes translation more difficult to implement, and may make it difficult to allow users to use pre-filtering. So I've split this off from the main issue for now.

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Note: the main challenge with EF support for VECTOR_SEARCH() as a TVF is that the .NET function would need to return some .NET type that wraps the original table contents and the score. However, EF's query pipeline does not currently support arbitrary CLR types that aren't mapped; anonymous types are well-supported, but the EF.Functions.VectorSearch() stub cannot return an anonymous type.