add pytest option to generate a functional report for distribution (#833)

# What does this PR do?

add pytest option (`--report`) to support generating a functional report
for llama stack distribution

## Test Plan
```
export LLAMA_STACK_CONFIG=./llama_stack/templates/fireworks/run.yaml
/opt/miniconda3/envs/stack/bin/pytest -s -v tests/client-sdk/  --report
```

See a report file was generated under
`./llama_stack/templates/fireworks/report.md`


## 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

@@ -80,7 +80,7 @@ class TestClientTool(ClientTool):
 
 
 @pytest.fixture(scope="session")
-def model_id(llama_stack_client):
+def text_model_id(llama_stack_client):
     available_models = [
         model.identifier
         for model in llama_stack_client.models.list()
@@ -92,14 +92,14 @@ def model_id(llama_stack_client):
 
 
 @pytest.fixture(scope="session")
-def agent_config(llama_stack_client, model_id):
+def agent_config(llama_stack_client, text_model_id):
     available_shields = [
         shield.identifier for shield in llama_stack_client.shields.list()
     ]
     available_shields = available_shields[:1]
     print(f"Using shield: {available_shields}")
     agent_config = AgentConfig(
-        model=model_id,
+        model=text_model_id,
         instructions="You are a helpful assistant",
         sampling_params={
             "strategy": {