[fed] Fixes for the encrypted GRPC backend. (#10503)

tests/test_distributed/test_gpu_federated/test_gpu_federated.py

@@ -0,0 +1,9 @@
+import pytest
+
+from xgboost.testing.federated import run_federated_learning
+
+
+@pytest.mark.parametrize("with_ssl", [True, False])
+@pytest.mark.mgpu
+def test_federated_learning(with_ssl: bool) -> None:
+    run_federated_learning(with_ssl, True, __file__)