ATOM-16747 RPISystemInterface::GetDefaultScene returns the scene crea… (#5153) (#5389)

* ATOM-16747 RPISystemInterface::GetDefaultScene returns the scene created by PreviewRenderer but not the Main Scene
Deprecate GetDefaultScene() function.
Update all the places which use GetDefaultScene to use Scene::GetFeatureProcessorFromEntityId or GetMainScene.
Tested with Editor, UI Editor, Material Editor, game launcher.

Signed-off-by: Qing Tao <55564570+VickyAtAZ@users.noreply.github.com>
(cherry picked from commit 8da6bea073)

Gems/AtomLyIntegration/AtomBridge/Code/Source/AtomBridgeSystemComponent.cpp

@@ -108,7 +108,7 @@ namespace AZ
         { 
             m_dynamicDrawManager.reset();
             AZ::RPI::ViewportContextManagerNotificationsBus::Handler::BusDisconnect();
-            RPI::Scene* scene = RPI::RPISystemInterface::Get()->GetDefaultScene().get();
+            RPI::Scene* scene = AZ::RPI::Scene::GetSceneForEntityContextId(m_entityContextId);
             // Check if scene is emptry since scene might be released already when running AtomSampleViewer 
             if (scene)
             {
@@ -157,9 +157,9 @@ namespace AZ
 
         void AtomBridgeSystemComponent::OnBootstrapSceneReady(AZ::RPI::Scene* bootstrapScene)
         {
-            AZ_UNUSED(bootstrapScene);
             // Make default AtomDebugDisplayViewportInterface
-            AZStd::shared_ptr<AtomDebugDisplayViewportInterface> mainEntityDebugDisplay = AZStd::make_shared<AtomDebugDisplayViewportInterface>(AzFramework::g_defaultSceneEntityDebugDisplayId);
+            AZStd::shared_ptr<AtomDebugDisplayViewportInterface> mainEntityDebugDisplay =
+                AZStd::make_shared<AtomDebugDisplayViewportInterface>(AzFramework::g_defaultSceneEntityDebugDisplayId, bootstrapScene);
             m_activeViewportsList[AzFramework::g_defaultSceneEntityDebugDisplayId] = mainEntityDebugDisplay;
         }