test(adapters): fix ruff lint errors in integration tests

- Remove unused schema_before variable (F841)
- Fix unsorted imports in test_llama_index.py (I001)

Author: polaz

tests/integration/adapters/test_langchain.py

@@ -119,7 +119,7 @@ def test_add_graph_documents_idempotent(graph, unique_tag):
 def test_schema_refreshes_after_add(graph, unique_tag):
     """structured_schema is invalidated and re-fetched after add_graph_documents."""
     graph._schema = None  # force refresh
-    schema_before = graph.schema
+    graph.schema  # trigger initial fetch before mutation
 
     node = Node(id=f"SchemaNode-{unique_tag}", type="LCSchemaTest")
     doc = GraphDocument(nodes=[node], relationships=[], source=Document(page_content="test"))

tests/integration/adapters/test_llama_index.py

@@ -12,7 +12,6 @@
 
 import pytest
 from llama_index.core.graph_stores.types import EntityNode, Relation
-
 from llama_index.graph_stores.coordinode import CoordinodePropertyGraphStore
 
 ADDR = os.environ.get("COORDINODE_ADDR", "localhost:7080")