Wordwrap NUX button

[mindgraffiti]

Fixes: wordpress-mobile/WordPressAuthenticator-iOS#155
Auth PR: wordpress-mobile/WordPressAuthenticator-iOS#452

There is an issue where iOS 12.0+ users on smaller devices do not get proper font scaling. This is an iOS 12 issue that doesn't happen on iOS 13. Instead of attempting to force iOS 12 to use the correct font scaling, we're going to word-wrap the long text in the button so it can be successfully read by the user.

Note that the buttons in the prologue are different because the UL&S project had updated designs to work from.

Before	After

To test

Use a small device or simulator on iOS 12, such as the iPhone SE or iPhone 5S.

1. Log out if logged in
2. Observe the prologue buttons

PR submission checklist:

• I have considered adding unit tests where possible.
• I have considered adding accessibility improvements for my changes.
• I have considered if this change warrants user-facing release notes and have added them to RELEASE-NOTES.txt if necessary.

[peril-wordpress-mobile]

You can trigger an installable build for these changes by visiting CircleCI here.

[peril-wordpress-mobile]

You can trigger optional UI/connected tests for these changes by visiting CircleCI here.

[ScoutHarris]

Looks good! Thanks for fixing this!!