Change optimizing_level to int to avoid "The output from the extension could not be parsed."

[mmrazik]

inkscape 1.3 creates a command like this on Windows: CutOptim.exe --unit=mm --distance=1 --max_length=1000.0 --optimizing_level=1.0 --original=false --firstpos=TL --free_rot=true --angle=90.0 --nested=true --debug_file=true C:\Users\aaa\AppData\Local\Temp\ink_ext_XXXXXX.svgRER8B2

This is the error: error parsing options: Argument '1.0' failed to parse

It is quite hard to figure out what is going on as this is the error in the UI: