Display errors when creating a process

Refs https://gitlab.com/arkindex/requests/-/issues/625

When a 400 is thrown by the backend when creating a process, the detailed error message is not displayed.

This occurs on GPU errors.

The JSON payload uses use_gpu key:

{"use_gpu":"The process is configured to use GPU, but does not include any workers that support GPU usage."}

But the detail is not displayed to the user