[Easy] Add Python Typing to inference.execute output function

Concerned method: [Packages/Inferences](https://github.com/guillaume-chervet/MLOpsPython/blob/2f902959a2b2de7bb25fed298dbcf8c9f3afb32c/packages/inference/src/mlopspython_inference/inference_pillow.py#L37)
We want to type this method.


You can create a dataclass:

```python
@dataclass
class InferenceOutput:
    prediction: str
    values: List[float]
```