Measure Segmenets LPE units changes the size of measurements (cm looks too large)

Summary:

Wrong measurements and wrong font/ arrow size when cm is used as a unit in document properties and/ or the path effect Measure Segments

Steps to reproduce/ what happens:

First issue is now reported in inkscape#1796

1. File - Document properties Display Unit cm Page Size A4, Add rectangular grid 1cm

   • Draw a rectangle
   • Path effect Measure Segments Unit mm: The lines are too thin, the number font is all to small and the measurements are wrong (instead of 60mm it reads 600mm)
   • Path effect Measure Segments Unit cm: The number font is all to small and the measurements are wrong (instead of 6cm it reads 60cm)

2. File > Document properties Display Unit mm Page Size A4, Add rectangular grid 1cm

   • Draw a rectangle
   • Path effect Measure Segments Unit mm: Behaves as expected
   • Path effect Measure Segments Unit cm: Measurements are right, arrows and helplines are way too big.

What should have happened?

Correct measurements, font and arrow size when using cm instead of mm as a unit

Sample attachments:

First issue	Second issue

Version info

1.0.2-2 (e86c870879, 2021-01-15)