New arcs have larger than expected stroke widths (e.g. 3px width becomes 3mm)

Steps to reproduce:

• Open Inkscape (should default to a mm document)
• Switch to the ellipse tool
• draw an ellipse
• add a stroke (note the width in the bottom left)
• change the ellipse to an arc/chord/segment by changing the start or end point
• draw another shape (either arc, chord, or segment)

What happened?

• Stroke is larger in the arc (difference is the mm to px ratio).

What should have happened?

• arc/chord/segment stroke width is the same as the circle

Version Info:

• Inkscape 1.2-dev (bf4f53e3, 2021-05-21) Linux Mint 20
• Inkscape 1.1-rc (abcfddf8, 2021-05-21) Linux Mint 20
• Bisection points to 803587e5

commit 803587e5b5296d081045c052a09af912a9e51e04
Author: Martin Owens <doctormo@gmail.com>
Date:   Wed Apr 28 20:08:32 2021 -0400

    Reset style_src on clear and propagate changes
    
    Style setting calls clear() which resets the style to default
    Fill is one of the very few styles that has a positive default in
    the svg specification (black) and if the style_src isn't reset
    it stops cascading from opening.
    
    We also make sure we are setting style_src after any clear() call.
    
    Attr::D is a special case where STYLE_PROP is not the default for
    style_src although future cleanup would be good.
    
    Fixes https://gitlab.com/inkscape/inkscape/-/issues/1961
    Fixes https://gitlab.com/inkscape/inkscape/-/issues/1651