chore: Update Gemini Live model names in live bidi streaming sample

The sample agent now uses updated model names for Gemini Live, including a new Vertex model as the default and a new AI Studio model option.

Co-authored-by: Hangfei Lin <[email protected]>
PiperOrigin-RevId: 828515811

Author: hangfei

contributing/samples/live_bidi_streaming_single_agent/agent.py

@@ -65,8 +65,9 @@ async def check_prime(nums: list[int]) -> str:
 
 
 root_agent = Agent(
-    # model='gemini-2.0-flash-live-preview-04-09',  # for Vertex project
-    model='gemini-2.0-flash-live-001',  # for AI studio key
+    model='gemini-live-2.5-flash-preview-native-audio-09-2025',  # vertex
+    # model='gemini-2.5-flash-native-audio-preview-09-2025',  # for AI studio
+    # key
     name='roll_dice_agent',
     description=(
         'hello world agent that can roll a dice of 6 sides and check prime'