:beetle: Fix slide not finishing hitting accept

Seems like _unhandled_key_input is called on node even if
is_processing_unhandled_input is true. Check if it's an engine bug.

godot/projector/slide/Slide.gd

@@ -29,6 +29,9 @@ func get_center():
 
 
 func _unhandled_key_input(event: InputEvent):
+	if not is_processing_unhandled_input():
+		return # seems to be hacky, see if it's an engine bug
+
 	if event.is_action("ui_accept") and event.is_pressed():
 		finished.emit()
 		get_viewport().set_input_as_handled()