Bridge relayer backwards compatibility for reading storage InboundLaneData/OutboundLaneData (#5921)

For permissionless lanes, we add `lane_state` to the `InboundLaneData`
and `OutboundLaneData` structs. However, for a period of time (until
both BHK and BHP are upgraded to the same version), we need the relayer
to function with runtimes where one has been migrated with `lane_state`
and the other has not. This PR addresses the incompatibility by
introducing wrapper structs for decoding without `lane_state`.