Fix iOS settings store code review issues

- Add AppGroupID key to Info.plist (group.com.rssuper.shared)
- Existing unit tests already cover SettingsStore functionality

This fix addresses issues identified in code review for FRE-538.

native-route/ios/RSSuper/Info.plist

@@ -18,6 +18,8 @@
 	<string>1.0</string>
 	<key>CFBundleVersion</key>
 	<string>1</string>
+	<key>AppGroupID</key>
+	<string>group.com.rssuper.shared</string>
 	<key>NSLocationWhenInUseUsageDescription</key>
 	<string>We need your location to provide nearby feed updates.</string>
 	<key>NSUserNotificationsUsageDescription</key>