fix: correct singleton test for ja4_common ClickHouseClient

get_client() returns a lazy ClickHouseClient wrapper — clickhouse_connect.get_client
is only called on .connect(), not at construction time. Remove incorrect assertion
that expected call_count==1 at module-level get_client() call.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

shared/python/ja4_common/tests/test_clickhouse.py

@@ -26,17 +26,15 @@ def test_client_reconnects_on_ping_fail():
 
 
 def test_get_client_returns_same_instance_on_second_call():
-    """get_client() is a singleton: returns the same object on repeated calls."""
+    """get_client() is a singleton: returns the same ClickHouseClient wrapper on repeated calls.
+    Note: clickhouse_connect.get_client is only called lazily on .connect(), not on get_client().
+    """
+    ch_module._client = None
+    c1 = get_client()
+    c2 = get_client()
+    assert c1 is c2
+    # Reset for other tests
     ch_module._client = None
-    with patch("ja4_common.clickhouse.clickhouse_connect.get_client") as mock_gc:
-        mock_inner = MagicMock()
-        mock_inner.ping.return_value = True
-        mock_gc.return_value = mock_inner
-        c1 = get_client()
-        c2 = get_client()
-        assert c1 is c2
-        # connect() should have been called once for c1; c2 reuses the same instance
-        assert mock_gc.call_count == 1
 
 
 def test_client_query_delegates_to_inner():