Hide editor_spin_slider grabber when closing Editor's windows
Hide editor_spin_slider grabber when closing Editor's windows

Fixes: #38740
(cherry picked from commit 095167dcc3cdca6264eff740a946970d79bca7e8)

ex/godot,ex/godot,ex/godot,ex/godot,ex/godot,ex/godot,ex/godot,ex/godot