Code cleanup: radio jammer (#29052)

* Code cleanup for radio jammer

* More Entity<T> for the people, and fix an accidental variable reuse

Content.Shared/Radio/Components/ActiveRadioJammerComponent.cs

@@ -0,0 +1,13 @@
+using Content.Shared.Radio.EntitySystems;
+using Robust.Shared.GameStates;
+
+namespace Content.Shared.Radio.Components;
+
+/// <summary>
+/// Prevents all radio in range from sending messages
+/// </summary>
+[RegisterComponent, NetworkedComponent]
+[Access(typeof(SharedJammerSystem))]
+public sealed partial class ActiveRadioJammerComponent : Component
+{
+}