Add polarisation spin state to ISIS ORSO file metadata

[adriazalvarez]

Description of work

Explained in #36685

Summary of work

Fixes #36685.

Further detail of work

1. In the original issue, is it described that the name of the workspaces contained in a group should be modified to contain the polarization as well as the theta angle. I have also included the name of the workspace in this string: {workspace_name}{theta}{polarization}.
2. I'm not sure that is possible to add the polarization header without adding an instrument settings header. This has the consequence of adding two fields on the instrument settings header: theta and wavelength. We agreed upon the standard values these fields should have, so they are written as null for files with polarization.

To test:

Run the following script, a file named corrected.ort should be saved on your default save directory.

CreateSampleWorkspace(OutputWorkspace='out_00', Function='User Defined', UserDefinedFunction='name=Lorentzian, Amplitude=48000, PeakCentre=2.65, FWHM=1.2', XUnit='wavelength', NumBanks=1, BankPixelWidth=1, XMin=0, XMax=16.5, BinWidth=0.1)
CreateSampleWorkspace(OutputWorkspace='out_11', Function='User Defined', UserDefinedFunction='name=Lorentzian, Amplitude=47000, PeakCentre=2.65, FWHM=1.2', XUnit='wavelength', NumBanks=1, BankPixelWidth=1, XMin=0, XMax=16.5, BinWidth=0.1)
CreateSampleWorkspace(OutputWorkspace='out_10', Function='User Defined', UserDefinedFunction='name=Lorentzian, Amplitude=22685, PeakCentre=2.55, FWHM=0.6', XUnit='wavelength', NumBanks=1, BankPixelWidth=1, XMin=0, XMax=16.5, BinWidth=0.1)
CreateSampleWorkspace(OutputWorkspace='out_01', Function='User Defined', UserDefinedFunction='name=Lorentzian, Amplitude=22685, PeakCentre=2.55, FWHM=0.6', XUnit='wavelength', NumBanks=1, BankPixelWidth=1, XMin=0, XMax=16.5, BinWidth=0.1)
group = GroupWorkspaces(['out_00','out_11','out_10','out_01'])
group = ConvertUnits(group, "Wavelength")

ws1 = CreateWorkspace([0.01, 17.0, 34.0], [50000, 50000])
eff = JoinISISPolarizationEfficiencies(P1=ws1,   P2=ws1, F1=ws1, F2=ws1)
eff = ConvertUnits(eff, "Wavelength")
eff = RebinToWorkspace(eff, group[0], True)

corrected = PolarizationCorrectionWildes([group[0], group[1], group[2], group[3]], Efficiencies=eff, AddSpinStateToLog=True)

#Not correct transformation but need q units to save the data
corrected = ConvertUnits(corrected,'MomentumTransfer')
SaveISISReflectometryORSO(corrected,'corrected.ort')

Once the file is saved, open the file as text and check that the following entries are added on the instrument settings header before each data columns:
polarization:pp,
polarization:pm,
polarization:mp,
polarization:mm

Added release notes

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[rbauststfc]

This is working really well for the majority of cases and the implementation is structured consistently with the rest of the code. Appropriate tests have been added. Great job getting to grips with the existing implementation on this one, there's a lot to get up to speed with.

The naming of datasets in the file currently isn't working for stitched polarised datasets. I've added some information below, but just let me know if you want to chat about this more and go through a demo of how to test this in the Reflectometry GUI.

I've also added a few suggestions from a maintainability/future-proofing perspective that might be worth considering.

[adriazalvarez]

Suggested change

	if self.is_polarized:
	self._name = f"{self._name} {self._spin_state}"
	return
	if self.is_polarized:
	self._name = f"{self._name} {self._spin_state}"
	return

Here I have decided to return early because if the dataset is polarized is not necessary to prepend the ws name for unique datasets and in some cases the ws name would be repeated.

[adriazalvarez]

I've built conda and standalone packages to test the Python Module. Everything seems to work correctly (tried on conda, windows and mac). I'll leave on draft as I still need to add a test for the module .

[sf1919]

For the moment I'll add a v6.12 milestone to this. It can always be changed if it looks like it won't get in by 16th January.

[rbauststfc]

Great job getting the import of the C++ constants to work, it's really nice for maintainability to be able to re-use those on the Python side too! Functionally the changes are all working really well for stitched and non-stitched datasets, and for workspace groups with and without polarisation corrections. 👍

I've added just a few minor comments, mostly just a couple of places where we might be able to make use of the log name constant. I've also suggested a slightly different update to the documentation about the dataset names, now that the logic for that has changed a little bit.

[rbauststfc]

All code review comments have been addressed. The code changes are looking good and working really well, with appropriate test coverage. Thanks very much for all your work on this @adriazalvarez!