Fix timeline cursor not updating on zoom change in the Bezier editor

(cherry picked from commit eee9d053a37c36007ca988dd2fa06a366e31e412)

editor/animation_bezier_editor.cpp

@@ -561,6 +561,7 @@ void AnimationBezierTrackEdit::set_root(Node *p_root) {
 }
 void AnimationBezierTrackEdit::_zoom_changed() {
 	update();
+	play_position->update();
 }
 
 String AnimationBezierTrackEdit::get_tooltip(const Point2 &p_pos) const {