Merge ActorSystem and IPlayerManager (#21314)

Content.Server/Alert/ServerAlertsSystem.cs

@@ -1,19 +1,7 @@
 using Content.Shared.Alert;
-using Robust.Server.GameObjects;
 
 namespace Content.Server.Alert;
 
 internal sealed class ServerAlertsSystem : AlertsSystem
 {
-    public override void Initialize()
-    {
-        base.Initialize();
-
-        SubscribeLocalEvent<AlertsComponent, PlayerAttachedEvent>(OnPlayerAttached);
-    }
-
-    private void OnPlayerAttached(EntityUid uid, AlertsComponent component, PlayerAttachedEvent args)
-    {
-        Dirty(component);
-    }
 }