fix(privacy): Update Shred behaviour to clear all cache data

[StephenHeaps]

• When using shred, clear all cache data. Wrapped in a feature flag so we can disable via Griffin.

Resolves brave/brave-browser#41095

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. Enable Shred (#brave-shred) & Shred Cache Data (#brave-shred-cache-data) feature flags, then restart the app.
2. Visit a site which stores 3rd-party cache (this can be checked in Settings -> Shields & Privacy -> Manage Website Data).
   • Ex. Visitinghttps://google.ca will show data from google.ca, gstatic.com, and google.com.
3. Visit Settings -> Shields & Privacy -> Manage Website Data to confirm there are entries with just Cache listed in the subtitle/description.
4. Tap & hold on the tab tray icon & tap 'Shred Site Data'.
   • Note: Shred on Tab Close has a delay before site is shredded. Shred on App Close will be resolved with [Shred] Tab and data not deleted when using 'App Close' for Auto Shred brave-browser#40484

Shred.Cache.Data.mp4

[brave-builds]

Released in v1.72.63

[Uni-verse]

Verified on iPhone 12 running iOS 18.0 using version 1.72 (75)

Using Test Plan in #25744 (comment)

Flags: #brave-shred, #brave-shred-cache-data

• Ensured all website data is deleted when Shredding using Shred Site Data in the tab bar icon.
• Ensured all website data is deleted when using Auto-Shred per site and globally (~30 secs delay).
• Ensured that favicon cache is removed from History.

example	example	example	example	example	example