bgpd: Ensure EVPN routes are not injected back into EVPN

bgpd: Ensure EVPN routes are not injected back into EVPN

EVPN type-2 and type-5 routes received with a L3 VNI and corresponding RTs
are installed into the appropriate BGP RIB. Ensure that these routes are not
re-injected back into EVPN as type-5 routes when type-5 advertisement is
enabled; only regular IPv4 routes (and IPv6 routes in future) in the RIB
should be injected into EVPN.

As a benefit of this change, no longer restrict that EVPN type-5 routes
should be non-host routes - i.e., allow /32 IPv4 routes (and /128 IPv6
routes in future).

Signed-off-by: Vivek Venkatraman <vivek@cumulusnetworks.com>
Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>
Signed-off-by: Mitesh Kanjariya <mitesh@cumulusnetworks.com>
Ticket: CM-19456
Reviewed By: CCR-7117
Testing Done:
1. Manual replication of problem and verification of fix
2. evpn-min