Added event to signal when the Editor is fully initialized so test scripts can listen for that instead of needed arbitrary wait commands. (#5623)

Signed-off-by: Chris Galvan <chgalvan@amazon.com>

Code/Framework/AzToolsFramework/AzToolsFramework/Application/ToolsApplication.cpp

@@ -214,12 +214,17 @@ namespace AzToolsFramework
             , public AZ::BehaviorEBusHandler
         {
             AZ_EBUS_BEHAVIOR_BINDER(EditorEventsBusHandler, "{352F80BB-469A-40B6-B322-FE57AB51E4DA}", AZ::SystemAllocator,
-                NotifyRegisterViews);
+                NotifyRegisterViews, NotifyEditorInitialized);
 
             void NotifyRegisterViews() override
             {
                 Call(FN_NotifyRegisterViews);
             }
+
+            void NotifyEditorInitialized() override
+            {
+                Call(FN_NotifyEditorInitialized);
+            }
         };
 
     } // Internal
@@ -443,6 +448,7 @@ namespace AzToolsFramework
                 ->Attribute(AZ::Script::Attributes::Module, "editor")
                 ->Handler<Internal::EditorEventsBusHandler>()
                 ->Event("NotifyRegisterViews", &EditorEvents::NotifyRegisterViews)
+                ->Event("NotifyEditorInitialized", &EditorEvents::NotifyEditorInitialized)
                 ;
 
             behaviorContext->EBus<ViewPaneCallbackBus>("ViewPaneCallbackBus")