AtomSampleViewerApplication standalone launch fix for changes to startup.

Signed-off-by: stankowi <[email protected]>

Standalone/Platform/Common/AtomSampleViewerApplication.cpp

@@ -9,6 +9,7 @@
 #include <AtomSampleViewerApplication.h>
 #include <SampleComponentManagerBus.h>
 
+#include <AzCore/Component/ComponentApplicationLifecycle.h>
 #include <AzCore/PlatformIncl.h>
 #include <AzCore/Component/ComponentApplication.h>
 #include <AzCore/Debug/Trace.h>
@@ -92,6 +93,11 @@ namespace AtomSampleViewer
 
         AzFramework::Application::StartCommon(systemEntity);
 
+        if (auto settingsRegistry = AZ::SettingsRegistry::Get(); settingsRegistry != nullptr)
+        {
+            AZ::ComponentApplicationLifecycle::SignalEvent(*settingsRegistry, "LegacySystemInterfaceCreated", R"({})");
+        }
+
         ReadTimeoutShutdown();
 
         WriteStartupLog();