Unbundle @jupyter-widgets/controls

[blois]

ipywidgets 8 has a few breaking changes- most of the ones in @jupyter-widgets/base have been mitigated but some large ones in @jupyter-widgets/controls persist- notably some of the text widgets (Text, Label, others) changed the name of the model.

Can@jupyter-widgets/controls be moved out of the core package and loaded from npm like all other widgets? This would effectively move those widgets out of the public API surface area and would not require deploying new versions of the colab-cdn-widget-manager to pick up changes in @jupyter-widgets/controls.

This is complicated by jupyter-widgets/ipywidgets#3560 where the *_module_version does not match the NPM version.

If controls cannot be unbundled then this requires deploying an ipywidgets v7 version and an ipywidgets v8 version in parallel (the public API remains unchanged, they can co-exist on a page), with the version chosen by checking the ipywidgets version at runtime in: https://github.com/googlecolab/colabtools/blob/62237b03aa6c760a1d008c4861168496b53be1a3/google/colab/output/_widgets.py#L34 when

[jasongrout]

See also the discussion at jupyter-widgets/ipywidgets#3524

In short, I think controls can be unbundled (assuming the version issue you point out is handled), but I didn't actually try it, so appropriate caveats there.