Template pages are displayed in wrong units (mm) in Pages tool toolbar

Summary:

When creating a new page, it's size (dimensionless) is in mm.

Steps to reproduce:

• open Inkscape with a new us letter sized document
• Create a rectangle that fit with the viewbox for reference.
• Create a new page (with the toolbar) and delete it (to add the page element)
• From the XML editor change the size of the rectangle and the page to width=8.5in and height=11in

What happened?

The rectangle stay the same size, but the page get resized by a 3.78 ratio

What should have happened?

The page should stay the same size, just using new units.

Version info

1.3.0