Fix #1651: Update Rewards UI based on if region is set to JP

[kylehickinson]

• "BAT" becomes "BAT Points" in most scenarios
• An additional disclaimer message is shown in the rewards summary (when non-empty)
• Powered by Uphold message is not shown in wallet details screen

Summary of Changes

This pull request fixes issue #1651

Submitter Checklist:

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

Test Plan:

• Verify all is normal in non-JP region
• Set device region to JP (language doesn't matter)
• Verify most places that say "BAT" now say "BAT Points" (exclusions: Tipping screen options)
• Verify that in wallet details the footer "Powered by Uphold" message is not visible
• Send a one-time tip to a verified publisher
• Verify that the JP disclaimer shows up in wallet summary
• Send a tip to an unverified publisher
• Verify both disclaimers appear in wallet summary

Screenshots:

BAT Points	Powered By Uphold
JP Disclaimer	Both Disclaimers

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).

[iccub]

Could you check if this looks good on iOS 12 with light and dark theme?
If not we would need to change this to appearanceBackgroundColor I believe

[kylehickinson]

It seemed to work?

Maybe I should change it to appearanceBackgroundColor anyways?

[iccub]

no, leave it as it is, we do not use this property in specific classes only in appearance proxies from what I see, theming is gonna drag us down a bit until we drop iOS 12 support