[network-data] fix IsOnMesh() to check on-mesh flags (#5116)
[network-data] fix IsOnMesh() to check on-mesh flags (#5116)

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