Allow bespoke input and output spin state in PolarizationCorrectionFredrikze

[rbauststfc]

Equivalent to #35067, but to be added to the PolarizationCorrectionFredrikze algorithm. This algorithm is not normally used by POLREF, but it would still be good to have the option to use it since it's offered as an option via the GUI.

The algorithm takes spin states directly as the input (unlike Wildes, which takes flipper configurations), so we need to add two new properties:

• Input spin state order - for specifying the order of the spin states in the input workspace group. Users should be able to specify either pp, pa, ap, aa, in any order, or p, a in either order. The tooltip supplied should make it clear that p is parallel and a is anti-parallel in this context, to avoid confusion with the Wildes algorithm input flipper configurations. This should also be explained clearly in the documentation. For backwards compatibility, the default value should be the input order that the algorithm currently uses.
• Output spin state order - for specifying the order of the spin states to be used for the output workspace group. Users should be able to specify either pp, pa, ap, aa, in any order, or p, a in either order. For backwards compatibility, the default value should be the output order that the algorithm currently uses.

PolarizationCorrectionFredrikze can be called via PolarizationEfficiencyCor, so PolarizationEfficiencyCor and it's documentation will need to be updated to support these changes.

Exposing the extra fields in the Reflectometry GUI will be covered separately under issue #37617.

This is part of the Polarised Reflectivity epic.