Bring SQL Server 2025 vector/JSON out of preview

We've merged support for various SQL Server 2025 functionality that's still in preview; the relevant APIs generally have `[Experimental]` on them. These features should come out of preview on the SQL Server side before we release 11, so we should do the necessary adjustments on the EF side when that happens:

* [`VECTOR_SEARCH()`](https://learn.microsoft.com/en-us/sql/t-sql/functions/vector-search-transact-sql?view=sql-server-ver17). The syntax will likely change here (TOP_N removal for pre-filtering support).
* [`CREATE VECTOR INDEX`](https://learn.microsoft.com/en-us/sql/t-sql/statements/create-vector-index-transact-sql).
* [`JSON_CONTAINS()`](https://learn.microsoft.com/en-us/sql/t-sql/functions/json-contains-transact-sql) (both the [Contains translation](https://github.com/dotnet/efcore/issues/36656) and the [EF.Function.JsonContains()](https://github.com/dotnet/efcore/issues/37566) translation. Specifically check what happens with a null item, a JSON item, an array item - these are currently unsupported, but if they are, we can unlock new translations via them (e.g. Contains over structural type collection (not just primitive), array-contained-within-array).