Fix UI for choosing a profile picture when user has no picture

Summary: Currently, we always show "current picture" even if you don't have one. In this case, the first available picture becomes the "current picture". Instead, show "current picture" only if there's actually a current picture to show.

Test Plan: {F49875}

Reviewers: btrahan, chad

Reviewed By: btrahan

CC: aran

Differential Revision: https://secure.phabricator.com/D6432
Improve "Ignore" action for setup warnings

Summary:
  - The dialog has no body text.
  - It uses an "Ignore" link because it predates action items.

Test Plan:
{F49894}
{F49895}
{F49896}

Reviewers: chad, btrahan

Reviewed By: chad

CC: aran

Differential Revision: https://secure.phabricator.com/D6433