Hide topsite customization option till we have add shortcut feature

[simonhong]

Resolves brave/brave-browser#12378
Resolves brave/brave-browser#12354

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:

A. Check customization toggle is hidden always.

B. Check most visited sites mode is on by default

1. Launch browser with clean profile
2. Load brave://prefs-internals/
3. check use_most_visited_tiles is set to true.

C. npm run test brave_browser_tests -- --filter=BraveProfilePrefsBrowserTest.*

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.

[bsclifton]

This value might be getting overridden by Chromium (I'm not 100% sure)

Basically in https://github.com/brave/brave-core/blob/master/components/brave_new_tab_ui/containers/newTab/gridSites.tsx#L78, the tile is becoming draggable. If you drag this tile, it does actually move it and then it seems to activate custom links mode

[bsclifton]

After troubleshooting, I re-ran npm run init for this branch and built... and it worked perfectly 😄 I believe the problem was on my side. Everything looks great!

[bsclifton]

Works perfect! Nice and easy solution

[kjozwiak]

Verification PASSED on macOS 10.15.7 x64 using the following build:

Brave | 1.19.13 Chromium: 87.0.4280.60 (Official Build) nightly (x86_64)
-- | --
Revision | 12697cfeb273d7de95cf9b18350d2c457f58224c-refs/branch-heads/4280@{#1352}
OS | macOS Version 10.15.7 (Build 19H2)

Case A

Ensured that the Customize Top Sites toggle under the Customization modal as been removed as per the following:

Case B

Ensured that use_most_visited_tiles is set as true under brave://prefs-internals as per the following:

However, I did run into brave/brave-browser#12739 while attempting to verify brave/brave-browser#12378. I think there's still some issues there re: re-adding websites into Top Sites once they've been removed.