Fix #1757: Show rewards onboarding to existing users when not in an ad-supported region

[Brandon-T]

When the user is OUT of ads region, and existing user, we can show rewards agreement.. There is no way for me to tell if rewards are available though :S

Which means, if the user is new, they complete onboarding up to shields. After some time, they upgrade or kill the app, now they are existing, and rewards show up which didn't show up previously.

Summary of Changes

This pull request fixes issue #1757

Submitter Checklist:

• Unit Tests are updated to cover new or changed functionality
• User-facing strings use NSLocalizableString()

Test Plan:

Screenshots:

Reviewer Checklist:

• Issues include necessary QA labels:
  • QA/(Yes|No)
  • release-notes/(include|exclude)
  • bug / enhancement
• Necessary security reviews have taken place.
• Adequate unit test coverage exists to prevent regressions.
• Adequate test plan exists for QA to validate (if applicable).
• Issue is assigned to a milestone (should happen at merge time).