[DRAFT] [MAINT] Reactivate GUI tests from the CI

[krzywon]

Description

This is currently a draft because I don't know if linux will handle the tests as well as Windows.

This is a comprehensive redo of the GUI tests. This includes a number of changes to fix a series of the tests, but I couldn't get them all working. Running the tests locally, I got pretty far, but need to stop where I am and move on to other things. Currently, 38 tests are labelled as skip or xfail, and four test files are not run (more below).

== 386 passed, 7 skipped, 31 xfailed, 226 warnings in 212.79s (0:03:32) ===

Things changed

• Enabled all GUI tests during the CI
• Many changes with the PyQt to PySide6 transition (I couldn't fix them all...)
• Enabled many tests previously marked as xfail and skip
• Disabled a few tests because of either PySide or underlying changes to the GUI that I couldn't fix myself.
• Moved the AddMultiEditorTest.py to a sub folder of Utilites\UnitTesting and added that directory to the pytest norecursedirs list (Loading the editor is segfaulting right now...)
• Added the Inversion perspective to the pytest norecursedirs list because of the major changes to it - most all of the tests currently fail
• Added the ParticleEditor perspective to the pytest norecursedirs list because it is still experimental and many of its tests fail
• Fixed some tests (that I could)

Fixes #2322

How Has This Been Tested?

Ran python -m pytest --disable-warnings -p no:logging .\src\sas\qtgui\ from the base sasview directory.

Review Checklist:

[Documentation (check at least one)

• 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 (untick if necessary)

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