This code changes rename the Test Your Settings button to
Test Settings to reduce the button width size.
By reducing button size it also impact the position of panel title to more centric.
Fixes https://gitlab.gnome.org/GNOME/gnome-control-center/-/issues/2123
This should significantly simplify these panels, by not forcing
them to override GObject.constructed all the time. Most panels
were quite straightfoward.
This one is an interesting case. It was easier to simply switch
to AdwPreferencesPage than actually port all the GtkFrames in
there.
In addition to that, the mouse test page now uses a GtkPicture
instead of a GtkImage, and the GtkDrawingArea API changes are
reflected in the code.
In Right-to-left locales GNOME Settings presents a button on the
left with the translated label "Right" and a button on the right
with the translated label "Left".
These changes prevent the flip of the direction buttons in RTL
locales.
Fixes#1101