What we really want is the gap style introduced in React Native 0.71.

To make it so we have a consistent 16px above, between, and below buttons, my approach in this diff is:

1. Add a RegistrationButtonContainer that always applies an 8px margin above and below buttons.
2. Make all RegistrationButtons apply an additional 8px margin above and below themselves.

Depends on D7831

With an artificially tall ConnectEthereum screen:

before	after

Other screens (which only have one button) are unchanged.