Persistent user tracking is possible using window.caches, by avoiding Brave Shields

## Summary: The recent version of iOS 15 introduced `window.caches` in WKWebView. It provides a persistent cache for web pages, and is also potentially usable for user tracking. The current [CookieControl.js](https://github.com/brave/brave-ios/blob/development/Client/Frontend/UserContent/UserScripts/CookieControl.js) disables cookie, localStorage and sessionStorage, but it doesn't disable `window.caches`, so it allows client-side user tracking by `window.caches` even when cookie brocker is enabled. ## Products affected: * Brave for iOS Version 1.41.1 (22.7.27.20) * iPhone 8 with iOS 15.6 ## Steps To Reproduce: * Enable Brave Shields and block all cookies * Visit https://csrf.jp/2022/caches.php * Push "Set Tracking ID" button, then your tracking ID is set to window.caches * Push "Get Tracking ID" button, then you can confirm your tracking ID that was set above * Close your browser and visit the above page again * Push "Get Tracking ID" button, then you can see your tracking ID again ## Supporting Material/References: * Attached is a movie file that demonstrate the above steps to reproduce. ## Impact As witten in summary, client-side user tracking by `window.caches` is possible even when cookie brocker is enabled.