No longer can create camera in an empty level (#5189)

Signed-off-by: Mikhail Naumov <mnaumov@amazon.com>

Code/Editor/EditorViewportWidget.cpp

@@ -1124,7 +1124,9 @@ void EditorViewportWidget::OnTitleMenu(QMenu* menu)
         action = menu->addAction(tr("Create camera entity from current view"));
         connect(action, &QAction::triggered, this, &EditorViewportWidget::OnMenuCreateCameraEntityFromCurrentView);
 
-        if (!gameEngine || !gameEngine->IsLevelLoaded())
+        const auto prefabEditorEntityOwnershipInterface = AZ::Interface<AzToolsFramework::PrefabEditorEntityOwnershipInterface>::Get();
+        if (!gameEngine || !gameEngine->IsLevelLoaded() ||
+            (prefabEditorEntityOwnershipInterface && !prefabEditorEntityOwnershipInterface->IsRootPrefabAssigned()))
         {
             action->setEnabled(false);
             action->setToolTip(tr(AZ::ViewportHelpers::TextCantCreateCameraNoLevel));

Gems/Camera/Code/Source/CameraEditorSystemComponent.cpp

@@ -20,6 +20,7 @@
 #include <AzToolsFramework/Entity/EditorEntityContextBus.h>
 #include <AzToolsFramework/API/EntityCompositionRequestBus.h>
 #include <AzToolsFramework/Entity/EditorEntityHelpers.h>
+#include <AzToolsFramework/Entity/PrefabEditorEntityOwnershipInterface.h>
 
 #include <AzToolsFramework/API/EditorCameraBus.h>
 #include "ViewportCameraSelectorWindow.h"
@@ -70,7 +71,20 @@ namespace Camera
         if (!(flags & AzToolsFramework::EditorEvents::eECMF_HIDE_ENTITY_CREATION))
         {
             QAction* action = menu->addAction(QObject::tr("Create camera entity from view"));
-            QObject::connect(action, &QAction::triggered, [this]() { CreateCameraEntityFromViewport(); });
+            const auto prefabEditorEntityOwnershipInterface = AZ::Interface<AzToolsFramework::PrefabEditorEntityOwnershipInterface>::Get();
+            if (prefabEditorEntityOwnershipInterface && !prefabEditorEntityOwnershipInterface->IsRootPrefabAssigned())
+            {
+                action->setEnabled(false);
+            }
+            else
+            {
+                QObject::connect(
+                    action, &QAction::triggered,
+                    [this]()
+                    {
+                        CreateCameraEntityFromViewport();
+                    });
+            }
         }
     }