refactor: add fixtures for client in test files to speed them up (#3490)

refactor: Add fixtures for client in test files to speed them up

src/backend/tests/unit/test_data_class.py

@@ -1,8 +1,14 @@
 import pytest
 from langchain_core.documents import Document
+
 from langflow.schema import Data
 
 
+@pytest.fixture
+def client():
+    pass
+
+
 def test_data_initialization():
     record = Data(text_key="msg", data={"msg": "Hello, World!", "extra": "value"})
     assert record.msg == "Hello, World!"