[snmp] Add wait portchannel up in test_snmp_fdb#13982

wangxin merged 1 commit intosonic-net:mastersonic-net/sonic-mgmt:masterfrom

yaqiangz:azure-master_fix_test_snmp_fdbyaqiangz/sonic-mgmt:azure-master_fix_test_snmp_fdbCopy head branch name to clipboard