ninja 2 electric boogaloo (#15534)

Co-authored-by: deltanedas <@deltanedas:kde.org>

Content.Server/Emp/EmpSystem.cs

@@ -31,6 +31,11 @@ public sealed class EmpSystem : SharedEmpSystem
     {
         foreach (var uid in _lookup.GetEntitiesInRange(coordinates, range))
         {
+            var attemptEv = new EmpAttemptEvent();
+            RaiseLocalEvent(uid, attemptEv);
+            if (attemptEv.Cancelled)
+                continue;
+
             var ev = new EmpPulseEvent(energyConsumption, false, false);
             RaiseLocalEvent(uid, ref ev);
             if (ev.Affected)
@@ -100,6 +105,13 @@ public sealed class EmpSystem : SharedEmpSystem
     }
 }
 
+/// <summary>
+/// Raised on an entity before <see cref="EmpPulseEvent"/>. Cancel this to prevent the emp event being raised.
+/// </summary>
+public sealed partial class EmpAttemptEvent : CancellableEntityEventArgs
+{
+}
+
 [ByRefEvent]
 public record struct EmpPulseEvent(float EnergyConsumption, bool Affected, bool Disabled);