Resolve all non-obsoleting warnings in content (#27934)

* Resolve all non-obsoleting warnings in content

* Update ClientGameTicker.cs

* Update SkeletonAccentSystem.cs

* Update BwoinkSystem.cs

Content.Server/Preferences/Managers/ServerPreferencesManager.cs

@@ -29,7 +29,6 @@ namespace Content.Server.Preferences.Managers
         [Dependency] private readonly IServerDbManager _db = default!;
         [Dependency] private readonly IPlayerManager _playerManager = default!;
         [Dependency] private readonly IDependencyCollection _dependencies = default!;
-        [Dependency] private readonly IPrototypeManager _protos = default!;
 
         // Cache player prefs on the server so we don't need as much async hell related to them.
         private readonly Dictionary<NetUserId, PlayerPrefData> _cachedPlayerPrefs =