Limit hydraulic clamps to one DoAfter at a time (#23982)

Limit Ripleys to one DoAfter at a time

Content.Server/Mech/Equipment/Components/MechGrabberComponent.cs

@@ -1,5 +1,6 @@
 using System.Numerics;
 using System.Threading;
+using Content.Shared.DoAfter;
 using Robust.Shared.Audio;
 using Robust.Shared.Containers;
 
@@ -47,4 +48,7 @@ public sealed partial class MechGrabberComponent : Component
 
     [ViewVariables(VVAccess.ReadWrite)]
     public Container ItemContainer = default!;
+
+    [DataField, ViewVariables(VVAccess.ReadOnly)]
+    public DoAfterId? DoAfter;
 }