module-eval: pin the collector off in the listener-count fixture

The case counting that fixture's listeners is about the addresses
declared on it. A collector on the same host adds a metrics listener,
so the expected count depended on a flag the case never mentions —
found by mutating the gate it sits next to, which failed both.

nix/module-eval.nix

@@ -108,6 +108,9 @@ let
   baoTwoAddresses = hive {
     deploy.bao.enable = true;
     deploy.bao.extraListenAddresses = [ "10.0.0.1" ];
+    # Pinned, not incidental: the case counting these listeners is about the
+    # declared addresses, and a collector on this host would add one of its own.
+    deploy.swarm-otel.enable = false;
   };
   # The store with and without a collector on the same host. `scrapeTargets`
   # is only ever read by a local collector, so the metrics endpoint is a