Remove unused import

Author: stellasia

tests/unit/test_message_history.py

@@ -12,7 +12,7 @@
 #  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 #  See the License for the specific language governing permissions and
 #  limitations under the License.
-from unittest.mock import MagicMock, ANY
+from unittest.mock import MagicMock
 
 import pytest
 from neo4j_graphrag.message_history import InMemoryMessageHistory, Neo4jMessageHistory