Check sync words count to be 24 (direct 1.40.x PR)

[AlexeyBarabash]

Resolves brave/brave-browser#23206

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:

1. Take Nightly browser (1.41.x)
2. Create a sync chain, copy sync code for desktop into clipboard
3. Take Beta (1.40.x)
4. Join the sync chain with words from the clipboard
5. It should give an error message

[AlexeyBarabash]

rebased to pass CI

[AlexeyBarabash]

rebased again to pass CI

[AlexeyBarabash]

Windows CI is unstable https://ci.brave.com/job/pr-brave-browser-fix_23206_1.40.x-windows-x86/3/consoleFull

13:29:30  [1108/1108] BraveSchemeLoadBrowserTest.CrashURLTest (TIMED OUT)
13:29:30  1 test timed out:
13:29:30      BraveSchemeLoadBrowserTest.CrashURLTest (../../brave/browser/brave_scheme_load_browsertest.cc:208)
13:29:30  null

not related to current PR

[kjozwiak]

Verification PASSED on both Ubuntu 22.04 x64 & Win 11 x64 using the following build that was provided by @AlexeyBarabash:

Brave | 1.40.84 Chromium: 102.0.5005.78 (Developer Build) (64-bit)
--- | ---
Revision | df6dbb5a9fd82af3f567198af2eb5fb4876ef99c-refs/branch-heads/5005_59@{#3}

• installed 1.40.84 Chromium: 102.0.5005.78 which includes the above fix on both Win 11 x64 & PopOS 22.04 x64
• generated a sync chain using 1.41.40 Chromium: 102.0.5005.78 which includes the new time-based sync codes
• ensured that the sync code generated from 1.41.40 Chromium: 102.0.5005.78 couldn't be restored as per the following:
  • ensured that an error message appears when restoring on Win 11 x64 using 1.40.84 Chromium: 102.0.5005.78
  • ensured that an error message appears when restoring on PopOS 22.04 x64 using 1.40.84 Chromium: 102.0.5005.78

Example	Example

Also ensured that sync codes that are not time-based can still be restored into 1.40.84 Chromium: 102.0.5005.78 without any issues. STR/Cases used:

• generated a sync chain using 1.39.111 Chromium: 102.0.5005.61 which doesn't have time-based sync backup codes
• ensured that the sync code generated from 1.39.111 Chromium: 102.0.5005.61 can be restored as per the following:
  • ensured that the PopOS 22.04 x64 device was added into the sync chain without issues
  • ensured that the Win 11 x64 device was added into the sync chain without issues

[kjozwiak]

Uplift into 1.40.x approved 👍