master: Commands bar is centered instead of left aligned

Summary:

Steps to reproduce:

• open Inkscape (after renaming the user config directory)

What happened?

see title / screenshot

What should have happened?

Commands bar should be left aligned.

Version info

Inkscape 1.5-dev (02ec16020f, 2025-07-25)

                      Compile  (Run)
    GLib version:     2.80.0
    GTK version:      4.14.5 (4.14.5)
    glibmm version:   2.78.1
    gtkmm version:    4.14.0
    libxml2 version:  2.9.14
    libxslt version:  1.1.39
    Cairo version:    1.18.0 (1.18.0)
    Pango version:    1.52.1 (1.52.1)
    HarfBuzz version: 8.3.0 (8.3.0)
    Poppler version:  24.02.0

    OS version:       Linux Mint 22.1