Resolve 'EntitySystem.Get<T>()' is obsolete in content (#27936)

* PROJECT 0 WARNINGS: Resolve `'EntitySystem.Get<T>()' is obsolete` in content

* pass entman

* dog ass test

* webeditor

Content.Server/GameTicking/Commands/ObserveCommand.cs

@@ -7,6 +7,8 @@ namespace Content.Server.GameTicking.Commands
     [AnyCommand]
     sealed class ObserveCommand : IConsoleCommand
     {
+        [Dependency] private readonly IEntityManager _e = default!;
+
         public string Command => "observe";
         public string Description => "";
         public string Help => "";
@@ -18,7 +20,7 @@ namespace Content.Server.GameTicking.Commands
                 return;
             }
 
-            var ticker = EntitySystem.Get<GameTicker>();
+            var ticker = _e.System<GameTicker>();
 
             if (ticker.RunLevel == GameRunLevel.PreRoundLobby)
             {