Fix tgi adapter (#796)

# What does this PR do?

- Fix TGI adapter

## Test Plan

<img width="851" alt="image"
src="https://github.com/user-attachments/assets/0084cbc6-6713-4079-b87b-0befd9aca0b0"
/>

- most inference working
- agent test failure due to model outputs

## Sources

Please link relevant resources if necessary.


## Before submitting

- [ ] This PR fixes a typo or improves the docs (you can dismiss the
other checks if that's the case).
- [ ] Ran pre-commit to handle lint / formatting issues.
- [ ] Read the [contributor
guideline](https://github.com/meta-llama/llama-stack/blob/main/CONTRIBUTING.md),
      Pull Request section?
- [ ] Updated relevant documentation.
- [ ] Wrote necessary unit or integration tests.

tests/client-sdk/agents/test_agents.py

@@ -98,7 +98,7 @@ def agent_config(llama_stack_client):
         instructions="You are a helpful assistant",
         sampling_params={
             "strategy": {
-                "type": "greedy",
+                "type": "top_p",
                 "temperature": 1.0,
                 "top_p": 0.9,
             },