`FeaturesManager.get_model_from_feature` should be a staticmethod
## Environment info
<!-- You can run the command `transformers-cli env` and copy-and-paste its output below.
     Don't forget to fill out the missing fields in that output! -->

- `transformers` version: 4.17.0
- Platform: Linux (Pop!_OS)
- Python version: 3.9.6
- PyTorch version (GPU?): 1.9.0+cu111
- Tensorflow version (GPU?): /
- Using GPU in script?: No
- Using distributed or parallel set-up in script?: No

### Who can help

@michaelbenayoun who committed #14358 

## Information

Type error for Pylance in VsCode: 
![Screenshot from 2022-03-22 23-42-33](https://user-images.githubusercontent.com/66584117/159596983-44a93943-7568-41af-8026-e99a1c2c06d1.png)

## Fix

https://github.com/huggingface/transformers/blob/77321481247787c97568c3b9f64b19e22351bab8/src/transformers/onnx/features.py#L336-L345

I believe the above function should have the `@staticmethod` decorator.
