[Icons]: Remove old icon overrides

[fallaciousreasoning]

Resolves brave/brave-browser#41086

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:

1. Icons in the chrome://settings menu should not have changed
2. Info icon when editing a BYOM model should still be present (next to the labels on the inputs)

[github-actions]

[puLL-Merge] - brave/brave-core@25577

Description

This PR removes custom Brave icons and replaces them with standard Chrome icons in the settings page. The main changes include:

1. Deletion of brave_icons.html file which contained custom SVG icons.
2. Removal of icon overrides in icons.ts.
3. Updates to various HTML files to use standard Chrome icons instead of custom Brave icons.
4. Removal of references to deleted files in build configuration.

The motivation for this change appears to be standardizing the icon usage across the settings page, likely to improve maintainability and consistency with the rest of the Chrome UI.

Changes

Changes

1. browser/resources/settings/brave_icons.html:

   • Deleted file containing custom SVG icons.

2. browser/resources/settings/brave_leo_assistant_page/model_config_ui.html:

   • Replaced brave_settings18:info icon with info-outline.

3. browser/resources/settings/brave_leo_assistant_page/model_list_section.html:

   • Replaced brave_settings20:edit-pencil with edit-pencil.
   • Replaced brave_settings20:trash-can with trash.

4. browser/resources/settings/brave_overrides/icons.ts:

   • Deleted file that contained icon overrides.

5. browser/resources/settings/brave_overrides/index.ts:

   • Removed import of deleted icons.js.

6. browser/resources/settings/brave_overrides/iron_icon.ts:

   • Added new icon mappings to standard Chrome icons.

7. browser/resources/settings/brave_overrides/settings_menu.ts:

   • Removed import of deleted brave_icons.html.js.

8. Various HTML files:

   • Updated icon references to use standard Chrome icons.

9. browser/resources/settings/sources.gni:

   • Removed references to deleted files and icons.

10. patches/chrome-browser-resources-settings-BUILD.gn.patch:

    • Removed reference to brave_settings_icons_html_files.

These changes collectively remove custom Brave icons and replace them with standard Chrome icons throughout the settings page.

[brave-builds]

A Storybook has been deployed to preview UI for the latest push

[brave-builds]

A Storybook has been deployed to preview UI for the latest push

[mkarolin]

patches++

[brave-builds]

A Storybook has been deployed to preview UI for the latest push