Zebra's clear duplicate detect command is rpc converted.
There is condition where cli fails with human readable message.
Using northboun's errmsg buffer to display error message to
user.
Testing:
bharat# clear evpn dup-addr vni 1002 ip 2011:11::11
Error type: generic error
Error description: Requested IP's associated MAC aa:aa:aa:aa:aa:aa is still in duplicate state
bharat# clear evpn dup-addr vni 1002 ip 11.11.11.11
Error type: generic error
Error description: Requested IP's associated MAC aa:aa:aa:aa:aa:aa is still in duplicate state