When not logged in or ethereum not enabled, clicking Submit Challenge button shows "not enough CVL" error

[tobek]

Ideally it would show a "not logged in" error or send you to login page (if we had ability to redirect back to appropriate page instead of to token storefront) in the first case, and in the second case it should pop up enable ethereum window.

[tobek]

This will crop up in many places, e.g. mentioned by Reid on slack https://civil-community.slack.com/archives/GHB235K2L/p1555027737036800 - if you're not logged in it says you didn't vote in the challenge.

Should we just pop up ethereum enable on every page view on registry?