[mlir][UBToLLVM] Do not arbitrarily restrict input types

The lowering pattern is currently restricted to integer, float and index types.
This is seemingly arbitrary, as `ub.poison` works for any input type. The lowering should therefore also work with any type that can be converted using the type converter.

This patch therefore simply removes that condition and adds a test ensuring that this works.

Differential Revision: https://reviews.llvm.org/D158982