Removes widget to return to the double stacked stats and top sites view for NTP

[alexsafe]

Resolves brave/brave-browser#21826

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:

[SergeyZhukovsky]

++. Nice clean up!

[AlexeyBarabash]

👍

[kjozwiak]

Verification PASSED on Samsung S10+ running Android 12 using the following build(s):

Brave | 1.40.4 Chromium: 101.0.4951.41 (Official Build) canary (32-bit)
--- | ---
Revision | 93c720db8323b3ec10d056025ab95c23a31997c9-refs/branch-heads/4951@{#904}
OS | Android 12; Build/SP1A.210812.016

• ensured that the widget isn't being displayed under the NTP
• ensured that the widget settings have been removed from Settings via New tab page
• ensured that the top tiles are pre-populated when opening a NTP on a new profile
  • note: the initial NTP that's opened on first launch doesn't display the tiles which is a known issue
• ensure that the following context items are working as expected when tapping/holding the tiles:
  • Open in new tab -> only when Enable Tab Group auto creation is disabled via Appearance
  • Open in new tab in group
  • Open in Private tab
  • Open in other window
  • Download link
  • Remove - ensured that Undo also works as expected
• ensured that the translucent background is also removed if the last tile has been removed
• ensured that tiles are being generated when visiting/browsing websites
• ensured that two rows of tiles are being displayed/working as expected when disabling Show background images
• ensured that re-enabling Show background images only displays a single row of tiles as expected
• ensured there's no issues when scrolling through Brave News
  • particularly making sure we're not running into scroll on NTP widget doesn't work well brave-browser#21511
• ensured there's no obvious issues with the NTP via PB (double checking to make sure this change didn't regress anything)
• upgraded from 1.39.11 Chromium: 100.0.4896.56 --> 1.40.4 Chromium: 101.0.4951.41 and ensured that the current tiles are retained

Example	Example	Example	Example	Example	Example