community[patch]: LanceDB integration patch update (#20686)

Description : 

- added functionalities - delete, index creation, using existing
connection object etc.
- updated usage 
- Added LaceDB cloud OSS support

make lint_diff , make test checks done

libs/community/tests/integration_tests/vectorstores/test_lancedb.py

@@ -1,30 +1,39 @@
+from typing import Any
+
 import pytest
 
 from langchain_community.vectorstores import LanceDB
 from tests.integration_tests.vectorstores.fake_embeddings import FakeEmbeddings
 
 
+def import_lancedb() -> Any:
+    try:
+        import lancedb
+    except ImportError as e:
+        raise ImportError(
+            "Could not import pinecone lancedb package. "
+            "Please install it with `pip install lancedb`."
+        ) from e
+    return lancedb
+
+
 @pytest.mark.requires("lancedb")
 def test_lancedb_with_connection() -> None:
-    import lancedb
+    lancedb = import_lancedb()
 
     embeddings = FakeEmbeddings()
-    db = lancedb.connect("/tmp/lancedb")
+    db = lancedb.connect("/tmp/lancedb_connection")
     texts = ["text 1", "text 2", "item 3"]
-    vectors = embeddings.embed_documents(texts)
-    table = db.create_table(
-        "my_table",
-        data=[
-            {"vector": vectors[idx], "id": text, "text": text}
-            for idx, text in enumerate(texts)
-        ],
-        mode="overwrite",
-    )
-    store = LanceDB(table, embeddings)
+    store = LanceDB(connection=db, embedding=embeddings)
+    store.add_texts(texts)
+
     result = store.similarity_search("text 1")
     result_texts = [doc.page_content for doc in result]
     assert "text 1" in result_texts
 
+    store.delete(filter="text = 'text 1'")
+    assert store.get_table().count_rows() == 2
+
 
 @pytest.mark.requires("lancedb")
 def test_lancedb_without_connection() -> None:

libs/community/tests/unit_tests/vectorstores/test_indexing_docs.py

@@ -67,6 +67,7 @@ def test_compatible_vectorstore_documentation() -> None:
         "FAISS",
         "HanaDB",
         "InMemoryVectorStore",
+        "LanceDB",
         "Milvus",
         "MomentoVectorIndex",
         "MyScale",