test: fix intermittent timeout in p2p_1p1c_network.py

The timeout is due to outstanding txrequests with
python peers. Fix this by disconnecting these peers
after they send their txns, they aren't needed after
this point anyway.

test/functional/p2p_1p1c_network.py

@@ -144,6 +144,11 @@ class PackageRelayTest(BitcoinTestFramework):
             for tx in transactions_to_presend[i]:
                 peer.send_and_ping(msg_tx(tx))
 
+        # Disconnect python peers to clear outstanding orphan requests with them, avoiding timeouts.
+        # We are only interested in the syncing behavior between real nodes.
+        for i in range(self.num_nodes):
+            self.nodes[i].disconnect_p2ps()
+
         self.log.info("Submit full packages to node0")
         for package_hex in packages_to_submit:
             submitpackage_result = self.nodes[0].submitpackage(package_hex)