test_serve: build the identity with the two-argument _build_identity

The introspection rate limit's removal dropped _build_identity's third
parameter; _hosted_protocols still passed it.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

Author: rustyconover

tests/test_serve.py

@@ -535,7 +535,7 @@ def _hosted_protocols(worker_cls: type[Worker]) -> frozenset[str]:
         worker_cls(quiet=True),
         enable_describe=False,
         server_version=_get_vgi_version(),
-        identity=_build_identity(worker_cls, None, None),
+        identity=_build_identity(worker_cls, None),
     )
     return frozenset(server.bindings)