INTPYTHON-787 Added check for AZURE_OPENAI_ENDPOINT test_graphrag.py and cleaned up closing clients (#232)

[Issue Key](https://jira.mongodb.org/browse/{ISSUE_KEY})

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This is a small bugfix. When we switched from including OPENAI_API_KEY
in CI secrets to using AZURE_OPENAI_ENDPOINTS, we missed this one.

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- Tests are run in github and evergreen. A passing patch build will be
included.

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- [ na] Did you update the changelog (if necessary)?
- [X] Is the intention of the code captured in relevant tests?
- [na] If there are new TODOs, has a related JIRA ticket been created?
- [X] Has a MongoDB Employee run [the patch build of this
PR](https://github.com/mongodb-labs/ai-ml-pipeline-testing?tab=readme-ov-file#running-a-patch-build-of-a-given-pr)?

- [x] Does the title of the PR reference a JIRA Ticket?
- [x] Do you fully understand the implementation? (Would you be
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- [x] Is all relevant documentation (README or docstring) updated?

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The author had thought of updating MongoDBGraphStore to be a context
manager. All this would do is close the client. We decided to leave it
with a close method only.

Author: caseyclements

libs/langchain-mongodb/tests/integration_tests/test_graphrag.py

@@ -201,27 +201,13 @@ def test_additional_entity_examples(entity_extraction_model, entity_example, doc
         assert len(new_entities) >= 2
 
 
-def test_chat_response(graph_store, query_connection):
-    """Displays querying an existing Knowledge Graph Database"""
-    answer = graph_store.chat_response(query_connection)
-    assert isinstance(answer, AIMessage)
-    assert "acme corporation" in answer.content.lower()
-
-
-def test_similarity_search(graph_store, query_connection):
-    docs = graph_store.similarity_search(query_connection)
-    assert len(docs) >= 4
-    assert all({"_id", "type", "relationships"}.issubset(set(d.keys())) for d in docs)
-    assert any("depth" in d.keys() for d in docs)
-    assert any("attributes" in d.keys() for d in docs)
-
-
 def test_validator(documents, entity_extraction_model):
     # Case 1. No existing collection.
-    client = MongoClient(CONNECTION_STRING)
     clxn_name = f"{COLLECTION_NAME}_validation"
-    client[DB_NAME][clxn_name].drop()
-    client.close()
+
+    with MongoClient(CONNECTION_STRING) as client:
+        client[DB_NAME][clxn_name].drop()
+
     # now we call with validation that can be added without db admin privileges
     store = MongoDBGraphStore(
         connection_string=CONNECTION_STRING,
@@ -243,16 +229,15 @@ def test_validator(documents, entity_extraction_model):
         collection = client[DB_NAME][clxn_name]
         collection.delete_many({})
 
-    store = MongoDBGraphStore(
-        collection=collection,
-        entity_extraction_model=entity_extraction_model,
-        validate=True,
-        validation_action="error",
-    )
-    bulkwrite_results = store.add_documents(documents)
-    assert len(bulkwrite_results) == len(documents)
-    collection.drop()
-    store.close()
+        store = MongoDBGraphStore(
+            collection=collection,
+            entity_extraction_model=entity_extraction_model,
+            validate=True,
+            validation_action="error",
+        )
+        bulkwrite_results = store.add_documents(documents)
+        assert len(bulkwrite_results) == len(documents)
+        collection.delete_many({})
 
     # Case 3: Existing collection without a validator
     with MongoClient(CONNECTION_STRING) as client: