Clear dirty flag after doing an initial save or save as in Asset Editor (#1033)

Code/Framework/AzToolsFramework/AzToolsFramework/AssetEditor/AssetEditorWidget.cpp

@@ -483,6 +483,8 @@ namespace AzToolsFramework
                         }
                     }
 
+                    m_dirty = false;
+
                     AddRecentPath(targetFilePath);
 
                     SetStatusText(Status::assetCreated);