fix: direct client pydantic type casting (#1145)

# What does this PR do?
- Closes #1142 
- Root cause is due to having `Union[str, AgenToolGroupWithArgs]`

## Test Plan
- Test with script described in issue. 

- Print out final converted pydantic object
<img width="1470" alt="image"
src="https://github.com/user-attachments/assets/15dc9cd0-f37a-4b91-905f-3fe4f59a08c6"
/>


[//]: # (## Documentation)

llama_stack/strong_typing/deserializer.py

@@ -325,7 +325,7 @@ class TupleDeserializer(Deserializer[Tuple[Any, ...]]):
                     f"type `{self.container_type}` expects a JSON `array` of length {count} but received length {len(data)}"
                 )
 
-        return tuple(item_parser.parse(item) for item_parser, item in zip(self.item_parsers, data))
+        return tuple(item_parser.parse(item) for item_parser, item in zip(self.item_parsers, data, strict=False))
 
 
 class UnionDeserializer(Deserializer):