PrimaryKey implementation should use client side indexes

[bfops]

Right now clients determine if rows match by calling a primary key compare func which just compares values in AlgebraicValue. Once we have client side indexes, we should just lookup the new value using the index to determine whether or not the current insert was an update.

Done for C# but not Typescript, Rust, Python

[bfops]

I think we may have other tickets for this? I think we've worked on this.