[llvm] [mlir] [mlir python] Add nanobind support for standalone dialects. (PR #117922)

[Peter Hawkins via llvm-commits]

hawkinsp wrote:

Hmm. It looks like some of the build bots don't have the extra dep, as folks guessed above. How does one fix that?

https://github.com/llvm/llvm-project/pull/117922