Revert "[CodeHealth] Use cxx20's T::contains pt.2 (#27709)"

[cdesouza-chromium]

This reverts commit b54f97e.

This PR is being reverted due build failures on x86:

 ../../brave/components/brave_news/browser/feed_sampling_unittest.cc(50,25): error: constexpr variable 'kGroups' must be initialized by a constant expression
14:55:44     50 |   static constexpr auto kGroups =
14:55:44        |                         ^
14:55:44     51 |       base::MakeFixedFlatSet<ContentGroup>({{"publisher_1", false},
14:55:44        |       ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
14:55:44     52 |                                             {"publisher_2", false},
14:55:44        |                                             ~~~~~~~~~~~~~~~~~~~~~~~
14:55:44     53 |                                             {"channel_1", true},
14:55:44        |                                             ~~~~~~~~~~~~~~~~~~~~
14:55:44     54 |                                             {"channel_2", true},
14:55:44        |                                             ~~~~~~~~~~~~~~~~~~~~
14:55:44     55 |                                             {"publisher_3", false}});
14:55:44        |                                             ~~~~~~~~~~~~~~~~~~~~~~~~
14:55:44  ../../brave/components/brave_news/browser/feed_sampling_unittest.cc(50,25): note: pointer to subobject of heap-allocated object is not a constant expression
14:55:44  ../../third_party/libc++/src/include\__memory/allocator.h(103,32): note: heap allocation performed here
14:55:44    103 |       return static_cast<_Tp*>(::operator new(__n * sizeof(_Tp)));
14:55:44        |                                ^
14:55:44  ../../brave/components/brave_news/browser/feed_sampling_unittest.cc(51,7): error: call to consteval function 'base::MakeFixedFlatSet<std::pair<std::string, bool>, std::less<void>, 5U>' is not a constant expression
14:55:44     51 |       base::MakeFixedFlatSet<ContentGroup>({{"publisher_1", false},
14:55:44        |       ^
14:55:44  ../../brave/components/brave_news/browser/feed_sampling_unittest.cc(51,7): note: pointer to subobject of heap-allocated object is not a constant expression
14:55:45  ../../third_party/libc++/src/include\__memory/allocator.h(103,32): note: heap allocation performed here
14:55:45    103 |       return static_cast<_Tp*>(::operator new(__n * sizeof(_Tp)));
14:55:45        |  

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:

[brave-builds]

Released in v1.77.57