temp workaround for #101326

Optimistic updates in object renderer

* notebooks: ensure preloads load before webview output is shown

This serializes code in the webview so that we make sure preloads load
before rending output. Since the rendering of HTML can be deferred,
we also potentially need to defer other actions like clearing and
focusing.

* fixup! rm debug code, comment

Fixes #101304

Re-focus webview when navigating back from another editor.

This prevents these actions from being reused by webviews

* Use controlled input for object renderer

* Display correct value widget based on key

* Remove TODO comment

Part of #100941