Update OpenAILLMService examples to use gpt-4.1

examples/foundational/23-bot-background-sound-p2p.py

@@ -4,15 +4,13 @@
 # SPDX-License-Identifier: BSD 2-Clause License
 #
 
-"""
-Usage
+"""Usage
 -----
 Set the path to your background audio file using the `INPUT_AUDIO_PATH` environment variable, then run the bot using:
 
     INPUT_AUDIO_PATH=path/to/your_audio.mp3 python 23-bot-background-sound.py
 
 Example:
-
     INPUT_AUDIO_PATH=my_audio.mp3 python 23-bot-background-sound.py
 """
 
@@ -71,7 +69,7 @@ async def run_bot(webrtc_connection: SmallWebRTCConnection):
         voice_id="71a7ad14-091c-4e8e-a314-022ece01c121",  # British Reading Lady
     )
 
-    llm = OpenAILLMService(api_key=os.getenv("OPENAI_API_KEY"), model="gpt-4o")
+    llm = OpenAILLMService(api_key=os.getenv("OPENAI_API_KEY"), model="gpt-4.1")
 
     messages = [
         {