[nrfconnect] Fix window-covering app build after adding EnableKey

The nRF Connect window-covering app didn't build correctly after recent
changes.

The fix is to move using the namespaces into another place in the code.

This change needs to be also applied in the SVE branch.

examples/window-app/nrfconnect/main/AppTask.cpp

@@ -53,6 +53,9 @@
 LOG_MODULE_DECLARE(app, CONFIG_MATTER_LOG_LEVEL);
 K_MSGQ_DEFINE(sAppEventQueue, sizeof(AppEvent), APP_EVENT_QUEUE_SIZE, alignof(AppEvent));
 
+using namespace ::chip;
+using namespace ::chip::Credentials;
+using namespace ::chip::DeviceLayer;
 namespace {
 
 // NOTE! This key is for test/certification only and should not be available in production devices!
@@ -83,10 +86,6 @@ constexpr uint32_t kOff_ms{ 950 };
 } // namespace StatusLed
 } // namespace LedConsts
 
-using namespace ::chip;
-using namespace ::chip::Credentials;
-using namespace ::chip::DeviceLayer;
-
 CHIP_ERROR AppTask::Init()
 {
     // Initialize CHIP stack