chore: add codemod for stabilizing ui (#8257)
### Description
Add codemod for the `experimentalUI` -> `ui` change that took place in
https://github.com/vercel/turbo/pull/8254
If `"experimentalUI": true` is set, then the config will be omitted as
the UI is now enabled by default.
### Testing Instructions
Added tests
CI should be green once https://github.com/vercel/turbo/pull/8258 lands
and we rebase
