Errors from remote tests

Intermittent errors (both on CI and when run locally) of the form:

```
E           pytket.extensions.quantinuum.backends.api_wrappers.QuantinuumAPIError: HTTP error attempting: job status.
E           
E           Server Response: {'error': {'code': 1, 'text': "object of type 'NoneType' has no len()"}}

../pytket/extensions/quantinuum/backends/api_wrappers.py:326: QuantinuumAPIError
```