[expect] fix CLI router tests (#5996)
[expect] fix CLI router tests (#5996)

The next hop here is not deterministic. This changes it to expect any
4-digit hex.
openthread/openthread,openthread/openthread,openthread/openthread,srickardti/openthread,jwhui/openthread,abtink/openthread,jwhui/openthread,srickardti/openthread,abtink/openthread,jwhui/openthread,jwhui/openthread,srickardti/openthread,abtink/openthread,abtink/openthread,srickardti/openthread,openthread/openthread