Errors when CanvasItemEditor updates

[groud]

Master branch.

Godot sprays errors on the CanvasItemEditor, when updating:

Probably here since #11446.

[marcelofg55]

I'm guessing that we should add another NULL check at line 2696 _draw_locks_and_groups(editor->get_edited_scene(), transform); to prevent the error spamming thing. Can you try this:

if (editor->get_edited_scene()) {
    _draw_locks_and_groups(editor->get_edited_scene(), transform);
}