Use updated recursive rm fs method for image-optimizer (#34210)
This ensures we handle `EEXISTS` with `fs.rmdir` for Node.js `v12` and use `fs.rm` when available instead as it is the replacement for `fs.rmdir` with the `recursive` option.
## Bug
- [x] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Errors have helpful link attached, see `contributing.md`
Fixes: https://github.com/vercel/next.js/issues/33860#issuecomment-1035676729
