[mlir] Add Float8E5M2FNUZ and Float8E4M3FNUZ types to MLIR

Float8E5M2FNUZ and Float8E4M3FNUZ have been added to APFloat in D141863.
This change adds these types as MLIR builtin types alongside Float8E5M2
and Float8E4M3FN (added in D133823 and D138075).

Reviewed By: krzysz00

Differential Revision: https://reviews.llvm.org/D143744