## What does this PR do?
We noticed that the passthrough inference provider doesn't work agent
due to the type mis-match between client and server. We manually cast
the llama stack client type to llama stack server type to fix the issue.
## test
run `python -m examples.agents.hello localhost 8321` within
llama-stack-apps
<img width="1073" alt="Screenshot 2025-03-11 at 8 43 44 PM"
src="https://github.com/user-attachments/assets/bd1bdd31-606a-420c-a249-95f6184cc0b1"
/>
fix https://github.com/meta-llama/llama-stack/issues/1560