test: fix idempotent close assertion in langfuse bridge test

Agent-Logs-Url: https://github.com/MervinPraison/PraisonAI/sessions/fd08f8d3-78b3-40b2-84b6-02c7bef43a2b

Co-authored-by: MervinPraison <454862+MervinPraison@users.noreply.github.com>

Author: Copilot

src/praisonai/tests/unit/test_langfuse_sink.py

@@ -495,7 +495,7 @@ def test_bridge_forwards_flush_and_close(self):
         sink._client.flush.assert_called_once()
 
         bridge.close()
-        # close() calls flush, so reset mock first
+        # close() is idempotent; second call should not flush again
         sink._client.flush.reset_mock()
         bridge.close()
-        sink._client.flush.assert_called_once()
+        sink._client.flush.assert_not_called()