TB 34403 [android]: Disable Normal mode by default.

...fenix/app/src/main/java/org/mozilla/fenix/HomeActivity.kt

...ix/app/src/main/java/org/mozilla/fenix/components/Core.kt

...rg/mozilla/fenix/components/toolbar/DefaultToolbarMenu.kt

.../app/src/main/java/org/mozilla/fenix/home/HomeFragment.kt

...a/org/mozilla/fenix/library/bookmarks/BookmarkFragment.kt

...a/org/mozilla/fenix/library/bookmarks/BookmarkItemMenu.kt

...main/java/org/mozilla/fenix/settings/HttpsOnlyFragment.kt

.../main/java/org/mozilla/fenix/settings/SettingsFragment.kt

...n/java/org/mozilla/fenix/settings/TabsSettingsFragment.kt

...org/mozilla/fenix/settings/search/SearchEngineFragment.kt

...main/java/org/mozilla/fenix/tabstray/TabLayoutMediator.kt

...rc/main/java/org/mozilla/fenix/tabstray/TabsTrayBanner.kt

...nix/app/src/main/java/org/mozilla/fenix/utils/Settings.kt

...android/fenix/app/src/main/res/values/preference_keys.xml

mobile/android/fenix/app/src/main/res/xml/preferences.xml

...nix/app/src/main/res/xml/private_browsing_preferences.xml

...app/src/test/java/org/mozilla/fenix/utils/SettingsTest.kt