Update magentic-one.md (#4903)

* Update magentic-one.md 

 Add openai extra to the installation instructions

* Update python/packages/autogen-core/docs/src/user-guide/agentchat-user-guide/magentic-one.md

---------

Co-authored-by: Eric Zhu <[email protected]>

Author: PratyushNag

python/packages/autogen-core/docs/src/user-guide/agentchat-user-guide/magentic-one.md

@@ -41,7 +41,7 @@ Be aware that agents may occasionally attempt risky actions, such as recruiting
 
 Install the required packages:
 ```bash
-pip install autogen-agentchat==0.4.0.dev13 autogen-ext[magentic-one]==0.4.0.dev13
+pip install autogen-agentchat==0.4.0.dev13 autogen-ext[magentic-one,openai]==0.4.0.dev13
 
 # If using the MultimodalWebSurfer, you also need to install playwright dependencies:
 playwright install --with-deps chromium