zebra: dup detected mac avoid update to bgpd

zebra: dup detected mac avoid update to bgpd

When a MAC is detected duplicate on a local
learn event (with freeze action),
do not send update to bgp to advertise into
evpn control plane.

With evpn mh, inform_client flag is set and
sends notification to bgp albeit dup detect
is set.

Check mac are detected as duplicate before
setting inform_client to true.

Ticket:CM-29817
Reviewed By:CCR-10329
Testing Done:

Enable DAD with freeze action
Upon local learn MAC detected as duplica

Signed-off-by: Chirag Shah <chirag@cumulusnetworks.com>