refs #26753

plots/__init__, plots__init__Test and helperfunctionsTest

Plotting a spectrum with one histogram without giving a specNum was
possible, however things like fitting and plot options needed a
spectrum to operate. Assign spec_num=1 to the WorkspaceArtist in these
cases.

Remove incorrect tests from helperfunctionTest

The tests were testing the behaviour of get_wksp_index_and_spec_num when
it was not passed either a wkspIndex or specNum. The code dealing with
this case has been pulled back into MantidAxes.plot so that the
calculated specNum can be set on the WorkspaceArtist. Hence the removed
tests are no longer needed.

Add SpinGlass to fit functions

Add missing kwarg for SANS GUI init

Fix crash when fitting tablews with column of type float

Fix ModHKL range, should be -0.5<q<=0.5

Updated Function Browser and related files

Add RFresonance to fit functions

Add Tools menu and slit calculator to reflectometry GUI

# Conflicts:
#	Framework/PythonInterface/test/python/plugins/functions/CMakeLists.txt

Add HighTFMuonium to fit functions

re #26876
# Conflicts:
#	Framework/PythonInterface/test/python/plugins/functions/CMakeLists.txt

Add StandardSC to fit function

re #26857
# Conflicts:
#	Framework/PythonInterface/test/python/plugins/functions/CMakeLists.txt

Add TFMuonium to fit functions

Add Meier function

Add SilverBaseline to fit function

re #26876
# Conflicts:
#	Framework/PythonInterface/test/python/plugins/functions/CMakeLists.txt

re #26857
# Conflicts:
#	Framework/PythonInterface/test/python/plugins/functions/CMakeLists.txt

Add StaticLorentzianKT to fit functions

re #26872
# Conflicts:
#	Framework/PythonInterface/test/python/plugins/functions/CMakeLists.txt