Remove memory warning when leaving app

LeCountdown/LeCountdownApp.swift

@@ -58,6 +58,7 @@ struct LeCountdownApp: App {
                 switch newPhase {
                 case .inactive:
                     Conductor.maestro.stopMainPlayersIfPossible()
+                    Conductor.maestro.memoryWarningReceived = false
                 case .active:
                     Logger.log("onChange(of: scenePhase) active")
                     Logger.log(Conductor.maestro.currentCountdowns.count)