Fix #96427

Fixes #96315

VS Code now calls `.delete` on the backup for you

Fixes #96419

Fixes #96421

Fixes #93214

* Fix widget in cell editor cutoff by the titlebar.

* Move zindex update internal to notebook

* remove unused css

* update zindex only closing notebook editor

* adopt fixed overflow widget option

* overflow visible is not needed for fixed element.

* optional transformOptimization

* remove unncessary position static and overflow visible

The new toggle editor type command lets you quickly switch between a custom editor and our default editor

Needs - sync language change to EH, and add status bar to markdown editor cells

Fixes #95615

When checking if we can persist a webview, we check to see if any reviver is registered for it. However this may activate extensions that register the reviver

For background webview that have been restored we can skip this check since we know they were persisted in the past