Python: added create_agent and removed need for Field in annotations (#380)

* added create_agent

* add minimal sample

* allow multiple annotations

* improved docstring

python/samples/getting_started/agents/foundry/foundry_basic.py

@@ -4,7 +4,6 @@ import asyncio
 from random import randint
 from typing import Annotated
 
-from agent_framework import ChatClientAgent
 from agent_framework.foundry import FoundryChatClient
 from pydantic import Field
 
@@ -23,8 +22,8 @@ async def non_streaming_example() -> None:
 
     # Since no Agent ID is provided, the agent will be automatically created
     # and deleted after getting a response
-    async with ChatClientAgent(
-        chat_client=FoundryChatClient(),
+    async with FoundryChatClient().create_agent(
+        name="WeatherAgent",
         instructions="You are a helpful weather agent.",
         tools=get_weather,
     ) as agent:
@@ -40,8 +39,8 @@ async def streaming_example() -> None:
 
     # Since no Agent ID is provided, the agent will be automatically created
     # and deleted after getting a response
-    async with ChatClientAgent(
-        chat_client=FoundryChatClient(),
+    async with FoundryChatClient().create_agent(
+        name="WeatherAgent",
         instructions="You are a helpful weather agent.",
         tools=get_weather,
     ) as agent: