[nrfconnect] Added reading stored onoff state in lighting app

OnOff cluster state is not read on lighting-app init, so the state
stored before reboot is not recovered.

examples/lighting-app/nrfconnect/main/ZclCallbacks.cpp

@@ -19,13 +19,15 @@
 #include "AppTask.h"
 #include "PWMDevice.h"
 
+#include <app-common/zap-generated/attributes/Accessors.h>
 #include <app-common/zap-generated/ids/Attributes.h>
 #include <app-common/zap-generated/ids/Clusters.h>
 #include <app/ConcreteAttributePath.h>
 #include <lib/support/logging/CHIPLogging.h>
 
 using namespace chip;
 using namespace chip::app::Clusters;
+using namespace chip::app::Clusters::OnOff;
 
 void MatterPostAttributeChangeCallback(const chip::app::ConcreteAttributePath & attributePath, uint8_t type, uint16_t size,
                                        uint8_t * value)
@@ -70,5 +72,17 @@ void MatterPostAttributeChangeCallback(const chip::app::ConcreteAttributePath &
  */
 void emberAfOnOffClusterInitCallback(EndpointId endpoint)
 {
+    EmberAfStatus status;
+    bool storedValue;
+
+    // Read storedValue on/off value
+    status = Attributes::OnOff::Get(1, &storedValue);
+    if (status == EMBER_ZCL_STATUS_SUCCESS)
+    {
+        // Set actual state to stored before reboot
+        GetAppTask().GetLightingDevice().InitiateAction(storedValue ? PWMDevice::ON_ACTION : PWMDevice::OFF_ACTION,
+                                                        AppEvent::kEventType_Lighting, reinterpret_cast<uint8_t *>(&storedValue));
+    }
+
     GetAppTask().UpdateClusterState();
 }