Fixed checking if LST exists

                # Read LST. Returns None if no LST is active

                lst_arr = self.camera.read_lens_shading_table()

                if lst_arr:

                if lst_arr is not None:

                    b64_string, dtype, shape = serialise_array_b64(lst_arr)

                    settings_current["camera"]["lens_shading_table"] = {