[Docs] Don't need open ai key for gpt4all model (#1018)

docs/get-started/faq.mdx

@@ -90,11 +90,8 @@ llm:
 <CodeGroup>
 
 ```python main.py
-import os
 from embedchain import Pipeline as App
 
-os.environ['OPENAI_API_KEY'] = 'xxx'
-
 # load llm configuration from opensource.yaml file
 app = App.from_config(config_path="opensource.yaml")
 ```