Comes from wordpress-mobile/WordPress-iOS#10565 and #8684 (comment)

Originally was intended to ship with #8695 (comment) but never did.

ToDo

(copied from #8684 (comment))
This is the logic we use to allow the user to switch between editors in iOS:

• If Gutenberg is enabled:
  • When in Aztec:
    • Show the option to switch to Gutenberg only if the post has blocks or is empty.
  • When in Gutenberg:
    • Show the option to switch to Aztec for all posts.
• If Gutenberg is not enabled:
  • Don't show the option