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()' is obsolete in content (#27936)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()' is obsolete` in content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/Atmos/Commands/ListGasesCommand.cs

@@ -8,13 +8,15 @@ namespace Content.Server.Atmos.Commands
     [AdminCommand(AdminFlags.Debug)]
     public sealed class ListGasesCommand : IConsoleCommand
     {
+        [Dependency] private readonly IEntityManager _e = default!;
+
         public string Command => "listgases";
         public string Description => "Prints a list of gases and their indices.";
         public string Help => "listgases";
 
         public void Execute(IConsoleShell shell, string argStr, string[] args)
         {
-            var atmosSystem = EntitySystem.Get<AtmosphereSystem>();
+            var atmosSystem = _e.System<AtmosphereSystem>();
 
             foreach (var gasPrototype in atmosSystem.Gases)
             {