fix: Add missing files_api parameter to MemoryToolRuntimeImpl test

The test_query_adds_vector_db_id_to_chunk_metadata test was failing because
MemoryToolRuntimeImpl.__init__() now requires a files_api parameter.

Fixes failing unit tests for Python 3.12 and 3.13.

tests/unit/rag/test_rag_query.py

@@ -88,6 +88,7 @@ class TestRagQuery:
             config=MagicMock(),
             vector_io_api=MagicMock(),
             inference_api=MagicMock(),
+            files_api=MagicMock(),
         )
 
         vector_db_ids = ["db1", "db2"]