Air alarm fixes (again, oops) (#7715)

* fixes critical issue

* alright, this might be the actual fix

* removes useless null checks

* couple more

* removes default functions from unary device data

Content.Server/Atmos/Monitor/Components/AirAlarmComponent.cs

@@ -24,7 +24,7 @@ namespace Content.Server.Atmos.Monitor.Components
 
         private AirAlarmSystem? _airAlarmSystem;
 
-        [ViewVariables] public AirAlarmMode CurrentMode { get; set; }
+        [ViewVariables] public AirAlarmMode CurrentMode { get; set; } = AirAlarmMode.Filtering;
 
         // Remember to null this afterwards.
         [ViewVariables] public IAirAlarmModeUpdate? CurrentModeUpdater { get; set; }