[posix] fix udp close (#5690)
[posix] fix udp close (#5690)


abtink/openthread,srickardti/openthread,openthread/openthread,bukepo/openthread,openthread/openthread,abtink/openthread,chshu/openthread,bukepo/openthread,openthread/openthread,openthread/openthread,bukepo/openthread,abtink/openthread,jwhui/openthread,chshu/openthread,srickardti/openthread,chshu/openthread,srickardti/openthread,chshu/openthread,bukepo/openthread,chshu/openthread,chshu/openthread,abtink/openthread,jwhui/openthread,srickardti/openthread,jwhui/openthread,jwhui/openthread