Backport FIX mouse notifications missings ->godot2

Backport Fix to this issue #17202

scene/main/scene_main_loop.cpp

@@ -566,6 +566,8 @@ void SceneTree::_notification(int p_notification) {
 			}
 		} break;
 		case NOTIFICATION_OS_MEMORY_WARNING:
+		case NOTIFICATION_WM_MOUSE_ENTER:
+		case NOTIFICATION_WM_MOUSE_EXIT:
 		case NOTIFICATION_WM_FOCUS_IN:
 		case NOTIFICATION_WM_FOCUS_OUT: {