NUX buttons are truncated on smaller devices

[frosty]

I just launched the app on the iPhone SE simulator, and noticed that the "continue with..." buttons in the NUX are truncated on smaller devices.

Per pbArwn-5X-p2, scale the button text to fit the width instead of truncating.

I guess we'll need to either wrap the text or shrink it when this happens.

[mindgraffiti]

Related host app issue: wordpress-mobile/WordPress-iOS#13466.

[ScoutHarris]

Reopening as this is no longer fixed with #213. For reference, the change that reverted the fix (in order to fix something else) was #216.

[mindgraffiti]

Also related: NUXButton doesn't shrink back down to the correct size when Dynamic Text is applied (make it a much larger size), then re-applied (set it back to normal).