Refactor reusable blocks to not depend on the editor module

[draganescu]

If we want the widgets editor to allow reusable blocks we need to refactor the reusable blocks functionality to not depend on @wordpress/editor as the widgets editor does not use this module.

@jorgefilipecosta added a few PRs to remove the dependency on @wordpress/editor from the Widgets editor and other places as sometimes the module is used as a convenience instead of for a real need.

[adamziel]

Solved by #25859