* Clear the clipboard after the seed phrase is pasted
On the "Import" page of the import onboarding flow, we now clear the
clipboard after the secret recovery phrase is pasted. This ensures that
the SRP isn't accidentally pasted somewhere else by the user, which can
be an easy and disastrous mistake to make.
* Clear clipboard during new onboarding flow as well
The beta build currently has a couple of UI elements (the horizontal
logo and the app header) set to "dark mode", even though nothing else
in our UI supports dark mode yet. These styles have been removed. We
should make the entire UI support dark mode all at once at a later
date.
Also the horizontal logo used for beta was named incorrectly; the dark
and non-dark logos were swapped. They have been switched back so that
the logo that ends with `-dark` is for dark mode.