Normalise wedge slicer phi to (-180,180]

[jellybean2004]

Description

This change updates WedgeSlicer.py, so the wedge phi parameter field in the slicer parameters window follows the same display convention as the plotted slice.

Generally, phi is restricted to (-180, 180]. When phi > 180 (negative value), but delta phi brings the wedge below 180 (positive value), the plot range shows values > 180 to show an unbroken plot. To this end, checks are implemented to match the field value to the range displayed on the plot.
For example, if phi = 190 (-170) but delta_phi = 15, the plot range will be 175-205, and the phi value displayed will be 190, not -170.

Fixes #3914

How Has This Been Tested?

Manually tested on Windows 11.

Review Checklist:

Documentation

• There is nothing that needs documenting
• Documentation changes are in this PR
• There is an issue open for the documentation (link?)

Installers

• There is a chance this will affect the installers, if so
  • Windows installer (GH artifact) has been tested (installed and worked)
  • MacOSX installer (GH artifact) has been tested (installed and worked)
  • Wheels installer (GH artifact) has been tested (installed and worked)

Licensing

• The introduced changes comply with SasView license (BSD 3-Clause)

[jellybean2004]

@pkienzle would you be willing to review this PR?

Please let me know if you are happy with the normalisation method used here.