Allow a Separate High Angle Bank Scale Factor to Be Defined in User File

[cailafinn]

Description of work

Adds the option to supply a front_scale value in the user file. This overrides a value given to rear_scale to be applied to the HAB workspaces.

Note: This PR modifies SANS TOML V1. Given that this parameter was already mentioned in the documentation for TOML V1 but didn't do anything, the decision was made to update the old format rather than updating

Also fixes a test class for the beam centre finder that wasn't in the CMakeLists.txt file and so wasn't being run.

Closes #39341
Closes #27948

To test:

1. Make a copy of the MaskFile.toml User file from the loqdemo.
2. In this copy, add a front_scale value to the [detector.configuration] section.
3. Launch workbench and open the ISIS SANS GUI
4. Load the original MaskFile.toml and batch_mode_reduction.csv files.
5. On the second_time run, enter the path to the front_scale copy into the User File box in the grid.
6. Run Everything
7. Plot the output files for the HAB and LAB onto separate plots for one of the runs
8. Drag over the workspaces for the other run to overplot them
9. Check that the LAB curves are the same and the HAB curve is using the scale you provided in the user file.

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