[MLIR][MemRefToLLVM] Remove last typed pointer remnants (#71113)

This commit removes the last typed pointer remnants from the MemRef to
LLVM conversions, including the transform dialect operation. Typed
pointers have been deprecated for a while now and it's planned to soon
remove them from the LLVM dialect.

Related PSA:
https://discourse.llvm.org/t/psa-removal-of-typed-pointers-from-the-llvm-dialect/74502