Add Llama 70B 3.3 to fireworks (#654)

# What does this PR do?

- Makes Llama 70B 3.3 available for fireworks

## Test Plan

```shell
pip install -e . \
&& llama stack build --config distributions/fireworks/build.yaml --image-type conda \
&& llama stack run distributions/fireworks/run.yaml \
  --port 5000
```

```python
        response = client.inference.chat_completion(
            model_id="Llama3.3-70B-Instruct",
            messages=[
                {"role": "user", "content": "hello world"},
            ],
        )
```

## Before submitting

- [ ] This PR fixes a typo or improves the docs (you can dismiss the
other checks if that's the case).
- [x] Ran pre-commit to handle lint / formatting issues.
- [x] 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.

llama_stack/providers/remote/inference/fireworks/fireworks.py

@@ -65,6 +65,10 @@ MODEL_ALIASES = [
         "fireworks/llama-v3p2-90b-vision-instruct",
         CoreModelId.llama3_2_90b_vision_instruct.value,
     ),
+    build_model_alias(
+        "fireworks/llama-v3p3-70b-instruct",
+        CoreModelId.llama3_3_70b_instruct.value,
+    ),
     build_model_alias(
         "fireworks/llama-guard-3-8b",
         CoreModelId.llama_guard_3_8b.value,