[Android] Fix for desktop mode

[samartnik]

Resolves brave/brave-browser#12382
Resolves brave/brave-browser#11928

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, npm run gn_check)
• Ran git rebase master (if needed).
• Ran git rebase -i to squash commits (if needed).
• Tagged reviewers and labelled the pull request as needed.
• Requested a security/privacy review as needed.
• Added appropriate QA labels (QA/Yes or QA/No) to the associated issue
• Added appropriate release note labels (release-notes/include or release-notes/exclude) to the associated issue
• 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-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-issues-with-tracking-protection
  • https://github.com/brave/brave-browser/wiki/QA-Guide

Test Plan:

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.

[SergeyZhukovsky]

++

[kjozwiak]

Verification PASSED on Samsung S10+ running Android 10 using 1.18.21 CR: 87.0.4280.27

• ensured that selecting Desktop site via Settings correctly displayed the check mark (selected)
• ensured that every page within that tab (Desktop Mode) is correctly loading desktop version of websites
• ensured disabling Desktop Mode starts using the mobile version of websites again
• ensured that Desktop Mode persists when closing/re-opening Brave
• ensured that Desktop Mode doesn't persists to other created tabs if already enabled
• ensured that you can have multiple tabs opened using Desktop Mode

---

Verification passed on Samsung Tab A with Android 10 running 1.18.21 x64 nightly build

• Verified Desktop mode is not enabled by default
• Verified visiting a mobile page and selecting desktop site from menu loads the page in desktop mode
• Verified enabling desktop mode from site settings auto enables and checks desktop mode in menu for each new tab
• Verified desktop mode is retained between relaunches
• Verified visiting a desktop page and reloading doesn't switch back to mobile page

---

Verification PASSED on Samsung Galaxy J3 version 5.1.1 running Bravearm 1.18.21 CR: 87.0.4280.27

• ensured that selecting Desktop site via Settings correctly displayed the check mark (selected)
• ensured that every page within that tab (Desktop Mode) is correctly loading desktop version of websites
• ensured disabling Desktop Mode starts using the mobile version of websites again
• ensured that Desktop Mode persists when closing/re-opening Brave
• ensured that Desktop Mode doesn't persists to other created tabs if already enabled
• ensured that you can have multiple tabs opened using Desktop Mode