refactor: update Ollama components to use langchain-ollama integration (#4369)

* refactor: reorganize langchain dependencies in pyproject.toml

* feat: add langchain-ollama dependency to pyproject.toml

* fix: update imports to use langchain_ollama for OllamaEmbeddings and ChatOllama

src/backend/base/langflow/components/embeddings/ollama.py

@@ -1,4 +1,4 @@
-from langchain_community.embeddings import OllamaEmbeddings
+from langchain_ollama import OllamaEmbeddings
 
 from langflow.base.models.model import LCModelComponent
 from langflow.field_typing import Embeddings

src/backend/base/langflow/components/models/ollama.py

@@ -2,7 +2,7 @@ from typing import Any
 from urllib.parse import urljoin
 
 import httpx
-from langchain_community.chat_models import ChatOllama
+from langchain_ollama import ChatOllama
 
 from langflow.base.models.model import LCModelComponent
 from langflow.field_typing import LanguageModel

src/backend/tests/unit/components/models/test_chatollama_component.py

@@ -2,7 +2,7 @@ from unittest.mock import MagicMock, patch
 from urllib.parse import urljoin
 
 import pytest
-from langchain_community.chat_models import ChatOllama
+from langchain_ollama import ChatOllama
 from langflow.components.models import ChatOllamaComponent