Ability to pick child nodes of scenes instances marked with "Editable children" to the "Add animation track/Pick node to be animated" dialog.

editor/scene_tree_editor.cpp

@@ -1145,7 +1145,7 @@ SceneTreeDialog::SceneTreeDialog() {
 
 	set_title(TTR("Select a Node"));
 
-	tree = memnew(SceneTreeEditor(false, false));
+	tree = memnew(SceneTreeEditor(false, false, true));
 	add_child(tree);
 	//set_child_rect(tree);