chore: auto-format generated types with prettier (#70405)
### What?
Added a step in both `build-native.cjs` and `build-wasm.cjs` scripts to
run Prettier on the generated types file after writing it.
Should have been added with #69680, but I didn't think about it.
Currently, every time you built the native module you have changes in
the git repo (which would be fixed on commit, but graphite might not be
happy with uncommitted changes).
