Include eth.link in public suffix only when include_private is true

[yrliou]

Resolves brave/brave-browser#17815

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
• 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:

Open https://swapr.eth.link/, should not show invalid cert error.

[yrliou]

Unrelated CI failure:
Android: unrelated s3 upload failure
Windows: unrelated browser test failure, AdBlockServiceTest.SubscribeToCustomSubscription
Merging.

[stephendonner]

Verified PASSED using

Brave	1.31.18 Chromium: 93.0.4577.63 (Official Build) nightly (x86_64)
Revision	ff5c0da2ec0adeaed5550e6c7e98417dac77d98a-refs/branch-heads/4577@{#1135}
OS	macOS Version 12.0 (Build 21A5506j)

Steps:

1. new profile
2. launched Brave
3. opened Developer Tools
4. chose the Network panel
5. loaded https://swapr.eth.link/

Confirmed I got a 200 OK from https://swapr.eth.link/

Verification PASSED on Win 10 x64 using the following build:

Brave | 1.31.23 Chromium: 93.0.4577.63 (Official Build) nightly (64-bit)
-- | --
Revision | ff5c0da2ec0adeaed5550e6c7e98417dac77d98a-refs/branch-heads/4577@{#1135}
OS | Windows 10 OS Version 2009 (Build 19042.1165)

When running through the above, I ran into an issue where the website 404 when attempting to load the locales json file. However, this is an issue on their end and not Brave related. Just a heads up for @brave/legacy_qa when we run through the above on 1.29.x. Example of the issue:

Example (Canada)	Example (Canada)

Example (USA)	Example (USA)

However, the page loads without any issues after a few refreshes and doesn't run into the certificate error that's mentioned via brave/brave-browser#17815 (comment). Example: