[Bug]: self._boundaries not created for `pybop.PSO`

[BradyPlanden]

Python Version

3.12

Describe the bug

For pybop.PSO, the self._boundaries attribute is not currently created:

PyBOP/pybop/optimisers/base_pints_optimiser.py

Line 143 in 9ac4d01

elif issubclass(self.pints_optimiser, PintsPSO):

As such, the optimiser exceeds acceptable values during optimisation.

Steps to reproduce the behaviour

Run the spm_pso.py example script and view the optimiser parameter vector.

Relevant log output

No response