Hide NTP VPN card when its group policy is disabled

[simonhong]

fix brave/brave-browser#42446

Resolves

Submitter Checklist:

• I confirm that no security/privacy review is needed and no other type of reviews are needed, or that I have requested them
• 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 wiki
  • npm run presubmit wiki, 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/Web-Compatibility-Exceptions-in-Brave
  • https://github.com/brave/brave-browser/wiki/QA-Guide
  • https://github.com/brave/brave-browser/wiki/P3A

Test Plan:

See the linked issue

[github-actions]

The security team is monitoring all repositories for certain keywords. This PR includes the word(s) "policy" and so security team members have been added as reviewers to take a look.

No need to request a full security review at this stage, the security team will take a look shortly and either clear the label or request more information/changes.

Notifications have already been sent, but if this is blocking your merge feel free to reach out directly to the security team on Slack so that we can expedite this check.

[bsclifton]

++

[brave-builds]

Released in v1.75.44

[MadhaviSeelam]

Verification PASSED using

Brave | 1.75.55 Chromium: 131.0.6778.85 (Official Build) nightly (64-bit)
-- | --
Revision | 3cc3ba11608e3bbbf9e053bdd032ec05e2a4db7f
OS | Windows 11 Version 24H2 (Build 26100.2314)

Please see additional steps on how to add/remove templates: brave/brave-browser#26502

1. Installed .175.55
2. launched Brave
3. logged into VPN as a new user (brave3vpn@mailinator)
4. enabled and disabled VPN
5. closed Brave
6. Follow steps 3-12 on how to download latest templates from Make Brave-specific options configurable through Windows Group Policy templates brave-browser#26502
7. navigate to Classic Administrative Templates >> Brave >> Brave Software settings folder
8. confirmed the actual policies are listed
9. navigated to Disable Brave VPN setting
10. confirmed Not configured is shown
11. edit the settings to Disabled Brave VPN to Enabled
12. relaunched Brave and confirmed Brave VPN card widget is not shown
13. edit the settings for Disabled Brave VPN again to Disabled
14. relaunched Brave and confirmed Brave VPN card widget is shown in disconnected state as expected.

step 4a	step 4b	step 8-9	step 10	step 11	step 12	step 13