Implement unsupported regions in Rewards linking flow.

[szilardszaloki]

Resolves brave/brave-browser#21209, resolves https://github.com/brave-intl/internal/issues/312.

Submitter Checklist:

• I confirm that no security/privacy review is needed, or that I have requested one
• There is a ticket for my issue
• Used Github auto-closing keywords in the PR description above
• Wrote a good PR/commit description
• Squashed any review feedback or "fixup" commits before merge, so that history is a record of what happened in the repo, not your PR
• Added appropriate labels (QA/Yes or QA/No; release-notes/include or release-notes/exclude; OS/...) to the associated issue
• Checked the PR locally: npm run test -- brave_browser_tests, npm run test -- brave_unit_tests, npm run lint, npm run gn_check, npm run tslint
• Ran git rebase master (if needed)

Reviewer Checklist:

• A security review is not needed, or a link to one is included in the PR description
• New files have MPL-2.0 license header
• Adequate test coverage exists to prevent regressions
• Major classes, functions and non-trivial code blocks are well-commented
• Changes in component dependencies are properly reflected in gn
• Code follows the style guide
• Test plan is specified in PR before merging

After-merge Checklist:

• The associated issue milestone is set to the smallest version that the
  changes has landed on
• All relevant documentation has been updated, for instance:
  • https://github.com/brave/brave-browser/wiki/Deviations-from-Chromium-(features-we-disable-or-remove)
  • https://github.com/brave/brave-browser/wiki/Proxy-redirected-URLs
  • https://github.com/brave/brave-browser/wiki/Fingerprinting-Protections
  • https://github.com/brave/brave-browser/wiki/Brave%E2%80%99s-Use-of-Referral-Codes
  • https://github.com/brave/brave-browser/wiki/Custom-Headers
  • https://github.com/brave/brave-browser/wiki/Web-Compatibility-Exceptions-in-Brave
  • https://github.com/brave/brave-browser/wiki/QA-Guide
  • https://github.com/brave/brave-browser/wiki/P3A

Test Plan:

In https://github.com/brave-intl/internal/issues/312.

[brave-builds]

A Storybook has been deployed to preview UI for the latest push

[szilardszaloki]

SonarCloud is reporting duplicated lines due to how we currently structure code in rewards_reducer.ts and wallet_reducer.ts (both on desktop and Android).

[emerick]

LGTM

[emerick]

Confirmed that the modal displays on Android as expected

.

[GeetaSarvadnya]

@szilardszaloki @emerick Can any one of you link the test plan here, please? also could you also mention the list of countries which doesn't support external wallet linkage (e.g Uphold/Gemini/Bitflyer). I have tried testing the PR in the latest nightly build 1.39.35 I am not getting the unsupported region message when I link Gemini/Uphold KYC'd accounts. Verified the PH and VN locales. Not sure what I am missing

cc: @LaurenWags @kjozwiak @Miyayes

[szilardszaloki]

Hey @GeetaSarvadnya!
I added the test plan to https://github.com/brave-intl/internal/issues/312, but just checked and it seems it got removed.
Reaching out via Slack!

[GeetaSarvadnya]

Verification PASSED on

Brave | 1.39.35 Chromium: 100.0.4896.79 (Official Build) nightly (64-bit)
-- | --
Revision | 8fb749dcab8700c24213791969e59deb72fee36f-refs/branch-heads/4896@{#1015}
OS | Windows 10 Version 21H2 (Build 19044.1586)

• Verified the unsupported region linkage error message for the wallet provider Gemini for the locale PH (Note: I had a discussion with @szilardszaloki, as per the discussion we have an account set up only for PH locale for Gemini provider, hence verified the PR only for Gemini wallet provider and PH locale)
  

[GeetaSarvadnya]

Verification PASSED on Samsung Galaxy Tab A7 version 11 running Bravemonoarmx64.apk_1.39.35

Verified the unsupported region linkage error message for the wallet provider Gemini for the locale PH