Fixes ads enabled by default for Japan on upgrade

[tmancey]

Fixes brave/brave-browser#6449

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:

• Confirm ads are not enabled by default for upgrade paths for new regions
• Confirm ads are enabled by default for fresh installs if a region is supported and rewards is enabled
• Confirm on-boarding is shown for upgrade paths for new regions

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.

[emerick]

LGTM

[masparrow]

👍 from me

[btlechowski]

LGTM, encountered few known issues while testing.

Brave	0.72.103 Chromium: 78.0.3904.50 (Official Build) nightly （64 ビット）
変更履歴	2accdc52c79976e264cd2694df6db31d1fccd8e8-refs/branch-heads/3904@{#658}
OS	Linux

Clean install, Japanese locale
Verified ads were enabled when rewards were enabled
Verified viewing an ad
Verified ads viewed increased in brave://rewards ads section

Upgrade from 0.69.x, Japanese locale
Verified ads are turned off by default on 0.69.x

Verified ads are turned off after upgrade to 0.72.x
Verified notification about ads available is shown after upgrade to 0.72.x

Verified that ads are not displayed after upgrade to 0.72.x
Verified clicking on Enable Ads in notification, opens brave://rewards
Verified that turning on ads, show the ads 0.72.x

Verified viewing an ad.
Verified ads viewed increased in brave://rewards ads section
Verified ad was added to ads history

Encountered brave/brave-browser#6088 brave/brave-browser#6207

Clean install, US locale
Verified ads were enabled when rewards were enabled
Verified viewing an ad
Verified ads viewed increased in brave://rewards ads section

Upgrade from 0.69.x, US locale
Verified ads are turned on by default on 0.69.x after enabling rewards
Verified ads are turned on after upgrade
Verified ads history retained after upgrade
Verified viewing an ad

Encountered brave/brave-browser#6270 (comment) when ads are turned off in 0.69.x

Clean install, Polish locale
Verified ads were enabled when rewards were enabled
Verified viewing an ad
Verified ads viewed increased in brave://rewards ads section

Upgrade from 0.69.x, Polish locale
Verified ads are turned off by default on 0.69.x
Verified ads are turned off after upgrade to 0.72.x
Verified notification about ads available is shown after upgrade to 0.72.x
Verified that ads are not displayed after upgrade to 0.72.x
Verified clicking on Enable Ads in notification, opens brave://rewards
Verified that turning on ads, show the ads 0.72.x
Verified viewing an ad.
Verified ads viewed increased in brave://rewards ads section
Verified ad was added to ads history

Clean install, Italian locale
Verified ads were enabled when rewards were enabled
Verified viewing an ad
Verified ads viewed increased in brave://rewards ads section

Upgrade from 0.69.x, Italian locale
Verified ads are turned off by default on 0.69.x
Verified ads are turned off after upgrade to 0.72.x
Verified notification about ads available is shown after upgrade to 0.72.x
Verified that ads are not displayed after upgrade to 0.72.x
Verified clicking on Enable Ads in notification, opens brave://rewards
Verified that turning on ads, show the ads 0.72.x
Verified viewing an ad.
Verified ads viewed increased in brave://rewards ads section
Verified ad was added to ads history

[kjozwiak]

@btlechowski awesome job on verifying this fix against Nightly 👍