[Bug]: Scheduled test failing on PyBaMM 23.5

[BradyPlanden]

Python Version

N/A

Describe the bug

Scheduled tests are failing on PyBaMM v23.5 as the Thevenin solution object did not obtain standard variables such as "Time [s]" until the following release. For more information see pybamm-team/PyBaMM#3129.

To fix this, we have a few options:

1. Add a catch for this error that we depreciate after we drop support for v23.5
2. Modify the PyBOP Thevenin class to not depend on the "Time [s]" for PyBaMM v23.5
3. Increment the PyBaMM dependency to no longer support v23.5

I'm in favour of 1 or 3. Since we control and package PyBaMM versioning within PyBOP there shouldn't be an issue with incrementing this dependency.

Steps to reproduce the behaviour

nox -s quick with PyBaMM v23.5

Relevant log output

https://github.com/pybop-team/PyBOP/actions/runs/8376046378