pjproject: ignore 192.0.0.0/29

From https://datatracker.ietf.org/doc/html/rfc7335#section-4
 " As defined in [RFC6333], this subnet
   is only present between the B4 and the Address Family Transition
   Router (AFTR) and never emits packets from this prefix "on the wire".
   464XLAT has the same need for a non-routed IPv4 prefix, and this same
   need may be common for other similar solutions"

Meaning that this candidate can be ignored. This is the second part of:

GitLab: #539
Change-Id: I52a906bc4ae5a1b1062cf6fe21dec216329c1d14