Interactive window- don't leave space for insert toolbar

[r3m0t]

Interactive window is more compact than Notebook now, by not leaving space for the insert cell toolbar(which has no items anyway in the interactive window)

This is cleaned up from #164760

[r3m0t]

@amunger I have cleaned up my previous PR you reviewed a long while ago. Could you take a look?

[rebornix]

should we check if the notebook document is readonly or not?

[r3m0t]

Yep, it is a bigger change now but it looks great. I used Show Contents on local history timeline/git timeline to see a readonly jupyter notebook.

[amunger]

insertToolbarBetweenCells should be set to false here if the notebook is readonly. That would eliminate the need to pass around the readonly parameter in all those other methods.

[r3m0t]

That information comes from the model, NotebookEditorWidget doesn't have the model in its constructor, only later when NotebookEditorWidget.setModel is called (which can be done multiple times)

Here's the call stack when using Show Contents on a git revision (creationOptions is { menuIds: {... }, cellEditorContributions: [ ...] })

Then setModel-

Then setOptions with isReadOnly set-

[r3m0t]

this is enough gap for the cellToolbar to have a gap between the top of the toolbar and the editor outline of the previous cell (in the case the previous cell has no output)

[r3m0t]

Thanks @amunger, users at my workplace will be very happy. During the change, I noticed #182120 as well.