Assign sTGC hit ID to the wire readout (ATLASSIM-3539)

sTGC hits are placed on the wire plane that is at the middle of the gas gap. Therefore, a sTGC hit identifier should be assigned to a wire readout element. Currently, when converting from hit ID to offline ID, the type of readout element is overwritten to ensure the new ID has the correct channel type. The MR prevents possible error if one forgets to redefine the ID. It is still recommended to redefine the ID after converting from hit ID to offline ID.