Consider integrating with other notebook environments like marimo

If the library used `https://github.com/manzt/anywidget` instead of hardcoding the dependency on `IPython` like in the checks in `ipython_integration.py`: ``` if IPython is None: raise RuntimeError("Cannot use `register_as_default` outside of IPython.") ``` we could also use these widgets in other notebook environments, like https://github.com/marimo-team/marimo