test(docker): update network-reuse harness fake ps output for egress-aware 3-field probe

test_docker_network_config.py landed on main after the #58489 revert and
stubbed docker ps with the 2-field ID\tState format. The re-landed
egress-aware reuse probe requests ID\tState\tEgressLabel when egress is
off, so the fake line failed to parse and the reuse path never fired.
Fixture-only change; production behavior is unchanged.

tests/tools/test_docker_network_config.py

@@ -130,7 +130,10 @@ def _reuse_guard_harness(monkeypatch, *, existing_mode: str, network: bool):
             stdout = ""
 
         if len(cmd) > 1 and cmd[1] == "ps":
-            Result.stdout = "existing-container-id\trunning\n"
+            # Matches the egress-aware reuse probe: with egress off the
+            # format string is ID\tState\tEgressLabel and docker renders a
+            # missing label as "<no value>".
+            Result.stdout = "existing-container-id\trunning\t<no value>\n"
         elif len(cmd) > 1 and cmd[1] == "inspect":
             Result.stdout = f"{existing_mode}\n"
         elif len(cmd) > 1 and cmd[1] == "run":