[Widgets editor] Why do we need to have a post id and use useEntityBlockEditor?

[adamziel]

Originally reported in #24290 (comment)

[adamziel]

It seems like even if we get rid of the "temporary post" entity record, we need something in it's place. The editor is rendered in the following way:

const [ blocks, onInput, onChange ] = useEntityBlockEditor(
	KIND,
	POST_TYPE,
	{ id: 'temporary-post-id' }
);
<BlockEditorProvider
	value={ blocks }
	onInput={ onInput }
	onChange={ onChange }
>
    <BlockList />
</BlockEditorProvider>

Which means we need something to pass to <BlockEditorProvider />. Of course we could just store blocks in react state, but we need to be able to access them in different places and that's what the store is for. So maybe we could replace POST_TYPE with some other/new entity, but it's just a cosmetic change and the overall mechanics would stay the same. I'll move forward with this data model then @jorgefilipecosta @draganescu @noisysocks @kevin940726

I'm closing this one for now, let's discuss and reopen as needed.