Revert "drop port-collision checks against swarm.otel.telemetryPort"

This reverts commit 627964f72d.

nix/host-modules/otel.nix

@@ -144,7 +144,9 @@ in
         the value *configured* rather than implied, which is the point of
         the option. An undeclared port is invisible to anything comparing
         ports, so a second collector on the same host picking the same
-        number fails at `bind()` rather than at eval.
+        number fails at `bind()` rather than at eval —
+        `services.hyperhive.swarm.otel.telemetryPort` sidesteps 8888 by
+        hand for that reason.
       '';
     };