Allow ghosts to hear radio message globally (#15078)

Content.Server/Radio/Components/ActiveRadioComponent.cs

@@ -14,4 +14,10 @@ public sealed class ActiveRadioComponent : Component
     /// </summary>
     [DataField("channels", customTypeSerializer: typeof(PrototypeIdHashSetSerializer<RadioChannelPrototype>))]
     public HashSet<string> Channels = new();
+
+    /// <summary>
+    ///     If this radio can hear all messages on all maps
+    /// </summary>
+    [DataField("globalReceive")]
+    public bool GlobalReceive = false;
 }