[BREAKING] Python: Add factory pattern to GroupChat and Magentic (#3224)

* group chat

* magentic

* Fix tests

* AI comments

* Unifiy error message and add warning

* misc

* Add overload

* Collapse orchestrator params

python/samples/semantic-kernel-migration/orchestrations/group_chat.py

@@ -233,11 +233,8 @@ async def run_agent_framework_example(task: str) -> str:
 
     workflow = (
         GroupChatBuilder()
-        .set_manager(
-            manager=AzureOpenAIChatClient(credential=credential).as_agent(),
-            display_name="Coordinator",
-        )
-        .participants(researcher=researcher, planner=planner)
+        .with_orchestrator(agent=AzureOpenAIChatClient(credential=credential).as_agent())
+        .participants([researcher, planner])
         .build()
     )
 

python/samples/semantic-kernel-migration/orchestrations/magentic.py

@@ -144,12 +144,7 @@ async def run_agent_framework_example(prompt: str) -> str | None:
         chat_client=OpenAIChatClient(),
     )
 
-    workflow = (
-        MagenticBuilder()
-        .participants(researcher=researcher, coder=coder)
-        .with_standard_manager(agent=manager_agent)
-        .build()
-    )
+    workflow = MagenticBuilder().participants([researcher, coder]).with_manager(agent=manager_agent).build()
 
     final_text: str | None = None
     async for event in workflow.run_stream(prompt):