Audit "Must Include" Fenix dependencies

• Audit Fenix code for tracking, fingerprintability, and safety features
• Make sure SessionStorage is not used in PBM on Android
• Make sure Fenix doesn't save history on disk
• Make sure TabCollections don't write in PBM on Android
• Isolate Icon loader on Android
• Audit Flexbox?
• Audit Lottie?

See: #33939 (comment 2605628) #33939 (comment 2605630)