mesh: reset sequence numbers on transition from iv update active to normal

test/mesh/mesh_access.c

@@ -1482,6 +1482,8 @@ static void mesh_access_secure_network_beacon_handler(uint8_t packet_type, uint1
         }
     } else {
         if (beacon_iv_update_active == 0){
+            // " At the point of transition, the node shall reset the sequence number to 0x000000."
+            mesh_lower_transport_set_seq(0);
             mesh_iv_update_completed();
         }
     }