handle invalid elements correctly

[alexneufeld]

improves https://forum.freecad.org/viewtopic.php?p=807080#p807996

before:

...
<class 'ValueError'>: invalid literal for int() with base 10: 'e81'
20:36:39  Sheet_Unfold: invalid literal for int() with base 10: 'e81'

after:

...
<class 'ValueError'>: Invalid shape name ?Face81
15:02:43  Sheet_Unfold: Invalid shape name ?Face81

[shaise]

Thanks!
I have also posted an issue that sheetmetal doen not wotk well with the new TNP mitigation. (although on RT version it works)

[alexneufeld]

Thanks! I have also posted an issue that sheetmetal done not wotk well with the new TNP mitigation. (although on RT version it works)

I've also noticed reference tracking failures on 1.1dev (I.E. in the trivial case of updated sheetmetal features with identical edges) I assume either we are doing something wrong here, or some portion of the toponaming python API changes didn't get ported over from RT version. Let me know if you want me to test anything specific 👍

[shaise]

Let me know if you want me to test anything specific

This is the issue and the test i used: FreeCAD/FreeCAD#18671