Stop requiring the initial time in NightLightStateMachine

We're only fooling ourselves if we think that it's ready *right* after
construction anyway. After all, the initial state of the lights won't be
updated when the state machine is constructed.

NightLight/Program.fs

@@ -77,7 +77,14 @@ let mainAsync _ =
         let mqttClientOptions = MqttClientOptionsBuilder().WithTcpServer(server).Build()
 
         let stateLock = new SemaphoreSlim(1, 1)
-        let mutable state = NightLightStateMachine DateTime.Now
+
+        let! initialState =
+            let emptyNightLightStateMachine = NightLightStateMachine()
+
+            TimeChanged DateTime.Now
+            |> handleEvent mqttClient logger emptyNightLightStateMachine
+
+        let mutable state = initialState
 
         mqttClient.add_ApplicationMessageReceivedAsync (fun e ->
             async {