Modify Agent API now supports model and embedding fields

The Modify Agent API now supports model and embedding fields to update the model and embedding used by the agent using the handles rather than specifying the entire configs.

1from letta_client import Letta
2client = Letta(
3 token="YOUR_API_KEY",
4)
5client.agents.modify(
6 agent_id="AGENT_ID",
7 model="openai/gpt-4o-mini",
8 embedding="openai/text-embedding-ada-002",
9)