fuzz fix: assert MAX_PEER_TX_ANNOUNCEMENTS is not exceeded

Previously this assertion checked MAX_PEER_TX_REQUEST_IN_FLIGHT was not
exceeded. However, this property is not actually enforced; it is just
used to determine when a peer is overloaded.

src/test/fuzz/txdownloadman.cpp

@@ -287,7 +287,7 @@ static void CheckInvariants(const node::TxDownloadManagerImpl& txdownload_impl,
     // We should never have more than the maximum in-flight requests out for a peer.
     for (NodeId peer = 0; peer < NUM_PEERS; ++peer) {
         if (!HasRelayPermissions(peer)) {
-            Assert(txdownload_impl.m_txrequest.CountInFlight(peer) <= node::MAX_PEER_TX_REQUEST_IN_FLIGHT);
+            Assert(txdownload_impl.m_txrequest.Count(peer) <= node::MAX_PEER_TX_ANNOUNCEMENTS);
         }
     }
     txdownload_impl.m_txrequest.SanityCheck();