Fix the distance for grabbing a EditorSpinSlider

Currently moving the mouse for a single pixel is enough to trigger
grabbing, which happens often unintentionally.

editor/gui/editor_spin_slider.cpp

@@ -106,7 +106,7 @@ void EditorSpinSlider::gui_input(const Ref<InputEvent> &p_event) {
 			}
 			grabbing_spinner_dist_cache += diff_x * grabbing_spinner_speed;
 
-			if (!grabbing_spinner && ABS(grabbing_spinner_dist_cache) > 4 * EDSCALE) {
+			if (!grabbing_spinner && ABS(grabbing_spinner_dist_cache) > 4 * grabbing_spinner_speed * EDSCALE) {
 				Input::get_singleton()->set_mouse_mode(Input::MOUSE_MODE_CAPTURED);
 				grabbing_spinner = true;
 			}