community[patch]: Voyage AI updates default model and batch size (#17655)

- **Description:** update the default model and batch size in
VoyageEmbeddings
    - **Issue:** N/A
    - **Dependencies:** N/A
    - **Twitter handle:** N/A

---------

Co-authored-by: fodizoltan <zoltan@conway.expert>

libs/community/tests/integration_tests/embeddings/test_voyageai.py

@@ -2,7 +2,7 @@
 from langchain_community.embeddings.voyageai import VoyageEmbeddings
 
 # Please set VOYAGE_API_KEY in the environment variables
-MODEL = "voyage-01"
+MODEL = "voyage-2"
 
 
 def test_voyagi_embedding_documents() -> None:
@@ -14,10 +14,22 @@ def test_voyagi_embedding_documents() -> None:
     assert len(output[0]) == 1024
 
 
+def test_voyagi_with_default_model() -> None:
+    """Test voyage embeddings."""
+    embedding = VoyageEmbeddings()
+    assert embedding.model == "voyage-01"
+    assert embedding.batch_size == 7
+    documents = [f"foo bar {i}" for i in range(72)]
+    output = embedding.embed_documents(documents)
+    assert len(output) == 72
+    assert len(output[0]) == 1024
+
+
 def test_voyage_embedding_documents_multiple() -> None:
     """Test voyage embeddings."""
     documents = ["foo bar", "bar foo", "foo"]
     embedding = VoyageEmbeddings(model=MODEL, batch_size=2)
+    assert embedding.model == MODEL
     output = embedding.embed_documents(documents)
     assert len(output) == 3
     assert len(output[0]) == 1024