This is to create an entry point into the editing workflow that will allow the user to choose whether to edit the article using the existing native wikitext editor, or VisualEditor by directing the user to an external browser app.

• Upon tapping the Edit pencil, the user will see a popup dialog that lets them select VE or native editor for this editing session, with an option to remember this choice.
• There will also be a new Settings option for the user to change this selection at any time afterwards.

(VE-side task: T422075)