Adds claim api for vg

[NejcZdovc]

Resolves brave/brave-browser#8354

Submitter Checklist:

• Submitted a ticket for my issue if one did not already exist.
• Used Github auto-closing keywords in the commit message.
• Added/updated tests for this change (for new code or code which already has tests).
• Verified that these changes build without errors on
  • Android
  • iOS
  • Linux
  • macOS
  • Windows
• Verified that these changes pass automated tests (unit, browser, security tests) on
  • iOS
  • Linux
  • macOS
  • Windows
• Verified that all lint errors/warnings are resolved (npm run lint)
• Ran git rebase master (if needed).
• Ran git rebase -i to squash commits (if needed).
• Tagged reviewers and labelled the pull request as needed.
• Request a security/privacy review as needed.
• Add appropriate QA labels (QA/Yes or QA/No) to include the closed issue in milestone
• Public documentation has been updated as necessary. 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-Protection-Mode
  • 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-issues-with-tracking-protection
  • https://github.com/brave/brave-browser/wiki/QA-Guide

Test Plan:

Plan 1:

• enable rewards
• claim ad grant and ugp
• connect to KYC uphold account
• make sure that ad grant was transferred to uphold while ugp stayed as VG

Plan 1:

• enable rewards
• connect to KYC uphold account
• disconnect uphold
• claim ad grant and ugp
• reconnect to uphold
• make sure that ad grant was transferred to uphold while ugp stayed as VG

Reviewer Checklist:

• New files have MPL-2.0 license header.
• Request a security/privacy review as needed.
• Adequate test coverage exists to prevent regressions
• Verify test plan is specified in PR before merging to source

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.

[zenparsing]

Since this logic is also in contribution_util.cc, I wonder if there might be a way to make this a single call, either by passing in ledger::is_testing or something similar.

[NejcZdovc]

everything passed except iOS, restarting iOS

[NejcZdovc]

CI failed on unrelated changes (audit-depos)

[LaurenWags]

Verified using

Brave	1.7.52 Chromium: 80.0.3987.132 (Official Build) nightly (64-bit)
Revision	fcea73228632975e052eb90fcf6cd1752d3b42b4-refs/branch-heads/3987@{#974}
OS	macOS Version 10.14.6 (Build 18G3020)

Verified the two test plans from the above description and 3 other scenarios. All are detailed below with steps.

---

PASS - Test plan 1 from PR description - #4708:

1. Install 1.7.52 and enable rewards (staging)
2. Restored a wallet with both ad and ugp grant
3. claim ad grant and ugp grant
4. connected a KYC'd uphold sandbox account
5. Confirmed that ad grant was transferred to uphold while ugp stayed as VG

[ RESPONSE - OnTransferAnonToExternalWallet ]
> time: 1583855549
> result: Success

[ RESPONSE - DeleteTokens ]
> time: 1583855549
> result: Success

---

PASS Test plan 2 from PR description - #4708:

1. Install 1.7.52 and enable rewards (staging)
2. Restore a wallet with both ad and ugp grants (do not claim yet)
3. connect to KYC'd uphold account
4. disconnect uphold
5. claim ad and ugp grants
6. Reconnect to Uphold
7. Confirmed that ad grant was transferred to uphold while ugp stayed as VG

[ RESPONSE - OnTransferAnonToExternalWallet ]
> time: 1583868941
> result: Success

[ RESPONSE - DeleteTokens ]
> time: 1583869920
> result: Success

claiming while disconnected:

reconnecting and ad grant is transferred to uphold:

---

PASS New User Scenario

1. Install Nightly 1.7.52, launch with flags for staging
2. Enable BR
3. Restore a wallet with an ad grant
4. Claim ad grant
5. Start wallet verification process (important, start with a non-kyc'd wallet and complete KYC process)
6. Get signed up acct KYC'd (may need to request in channel)
7. Launch again (with logging info)
8. Confirm you get notification that your KYC is complete
9. Confirm in logs that ad grant BAT is sent to Uphold - confirmed OnTransferAnonToExternalWallet and DeleteTokens were successful.

[ RESPONSE - OnTransferAnonToExternalWallet ]
> time: 1583853683
> result: Success

[ RESPONSE - DeleteTokens ]
> time: 1583853684
> result: Success

---

PASS - Upgrade test 1 (partially spend ad grant)

1. Install 1.4.x (staging env).
2. Restore a wallet with an ad grant and ugp grant (do not claim yet).
3. Connect KYCd wallet.
4. Claim ad grant first.
5. Claim ugp grant second.
6. Tip a KYC'd publisher (such as 3zsistemi.si) 1 BAT.
7. Upgrade to Nightly 1.7.52.
8. Confirm remaining ad grant is moved to Uphold.
9. Confirm UGP grant remains VG.

[ RESPONSE - OnTransferAnonToExternalWallet ]
> time: 1583857710
> result: Success

[ RESPONSE - DeleteTokens ]
> time: 1583857711
> result: Success

---

PASS - Upgrade test 2 (no spending of ad grant)

1. Install 1.4.x (staging env).
2. Restore a wallet with an ad grant and ugp grant (do not claim yet).
3. Connect KYCd wallet.
4. Claim ad grant.
5. Upgrade to Nightly 1.7.52.
6. Confirm entire ad grant is moved to Uphold.

[ RESPONSE - OnTransferAnonToExternalWallet ]
> time: 1583858357
> result: Success

[ RESPONSE - DeleteTokens ]
> time: 1583858358
> result: Success