In some cases selecting a field to change its value make this value invisible.
It happens until the dialog is resized, so I am guessing there is a problem
when initializing sizers settings.
Old .sch files do not store the symbol part description (stored in a cache lib)
So when using a .sch file, the part description can be not existing.
The fix tests for non existing part description.
Fixes#6580https://gitlab.com/kicad/code/kicad/issues/6580
Stop trying to make a read only wxTextCtrl with a custom font work
for displaying the symbol library identifier and use an ellipsized
wxStaticText control with the standard font instead.
Fixes https://gitlab.com/kicad/code/kicad/-/issues/6240