Unsaved changes dialog displays incorrect GCode Flavor

[craiglink]

Describe the bug
When changing GCode Flavors and switching between printers, the wrong name of the GCode flavor is displayed. This is present in PrusaSlicer. Fix included

To Reproduce
Steps to reproduce the behavior:

1. Add to printers to SuperSlicr
2. Change the GCode Flavor to one ( Marlin -> Klipper ) without saving
3. Toggle to the second printer
4. Unsaved Changes Dialog is displayed showing the incorrect GCode Flavor names

>> Project File <<

Expected behavior
Correct and Selected GCode Flavors should be displayed

Screenshots
If applicable, add screenshots to help explain your problem.

Desktop (please complete the following information):

• OS: Windows
• Version 2.3.56.1

Additional context
The issue is that the function in UnsaveChangesDialog.cpp
get_string_from_enum() makes the assumption that enums are added to the enum_labels and enum_values vectors in numerical order. This is not the case as "klipper" is added in the 6th position but has an enum value of 7 - https://github.com/supermerill/SuperSlicer/blob/master/src/libslic3r/PrintConfig.cpp#L1901

The code already handles a case where all enum values arent in these vectors for infill. This same code path should be used for all enums displayed in the UnsavedChangesDialog since the performance hit to render this dialog would be minimal

[craiglink]

see #1239 for fix