chore: Make privacy url not configurable

lib/config/app_config.dart

@@ -50,4 +50,10 @@ abstract class AppConfig {
     host: 'servers.joinmatrix.org',
     path: 'servers.json',
   );
+
+  static final Uri privacyUrl = Uri(
+    scheme: 'https',
+    host: 'github.com',
+    path: '/krille-chan/fluffychat/blob/main/PRIVACY.md',
+  );
 }

lib/config/setting_keys.dart

@@ -52,10 +52,6 @@ enum AppSettings<T> {
   // AppConfig-mirrored settings
   applicationName<String>('chat.fluffy.application_name', 'FluffyChat'),
   defaultHomeserver<String>('chat.fluffy.default_homeserver', 'matrix.org'),
-  privacyUrl<String>(
-    'chat.fluffy.privacy_url',
-    'https://github.com/krille-chan/fluffychat/blob/main/PRIVACY.md',
-  ),
   // colorSchemeSeed stored as ARGB int
   colorSchemeSeedInt<int>(
     'chat.fluffy.color_scheme_seed',