Limit branching to only lists with 10 or fewer options (for now)

[lfdebrux]

What problem does this pull request solve?

Trello card: https://trello.com/c/pOOto1kO/3098-limit-branching-to-only-lists-with-10-or-fewer-options-for-now

We've decided for now to avoid presenting form creators with a very long routing page if they have a selection question with a long list of options.

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• Ensure that you consider the wider context.
• Does it work when run on your machine?
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• Do the commit messages explain why the changes were made?
• Are there all the unit tests needed?
• Do the end to end tests need updating before these changes will pass?
• Has all relevant documentation been updated?

[github-actions]

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[thomasiles]

nicely done 🏅