test(cli_tools_click): mock get_app_or_root_agent in eval CLI tests

The eval CLI now resolves agents via `get_app_or_root_agent`. Update
the shared `mock_get_root_agent` fixture in test_cli_tools_click.py to
patch the new resolver and yield `(None, root_agent)`, matching the
non-App path the eval-set-id tests exercise.

Author: saifer82

tests/unittests/cli/utils/test_cli_tools_click.py

@@ -59,8 +59,16 @@ def mock_load_eval_set_from_file():
 
 @pytest.fixture
 def mock_get_root_agent():
-  with mock.patch("google.adk.cli.cli_eval.get_root_agent") as mock_func:
-    mock_func.return_value = root_agent
+  """Patches the agent resolver used by the eval CLI.
+
+  `cli_eval` resolves agents via `get_app_or_root_agent` (which returns
+  `(app, root_agent)`); the eval-set tests don't exercise the App path,
+  so we yield `(None, root_agent)`.
+  """
+  with mock.patch(
+      "google.adk.cli.cli_eval.get_app_or_root_agent"
+  ) as mock_func:
+    mock_func.return_value = (None, root_agent)
     yield mock_func