fix event logger for ContentDelta update (#83)

# What does this PR do?

Issue

<img width="843" alt="image"
src="https://github.com/user-attachments/assets/839eecf4-2279-4511-9c8b-f6e94b14bb4b"
/>


## Test Plan

<img width="842" alt="image"
src="https://github.com/user-attachments/assets/2bfac820-9856-4b8d-975e-55c052b5aca2"
/>


## 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.

src/llama_stack_client/lib/inference/event_logger.py

@@ -28,6 +28,6 @@ def log(self, event_generator):
             if event.event_type == "start":
                 yield LogEvent("Assistant> ", color="cyan", end="")
             elif event.event_type == "progress":
-                yield LogEvent(event.delta, color="yellow", end="")
+                yield LogEvent(event.delta.text, color="yellow", end="")
             elif event.event_type == "complete":
                 yield LogEvent("")