Push2: Mostly fix scale menu text rendering (#8599)

"Mostly" because there are still some issues with horizontal overlap between
entries, but I think that's something that needs to be addressed separately.

Like earlier issues, this was caused by using a screen-derived or default
cairo/pango context.  I also tinkered with some constants to make things look
sensible to me, and hopefully everywhere since it should always look the same
with the context fix.

libs/surfaces/push2/push2.cc

@@ -52,7 +52,6 @@
 #include "canvas.h"
 #include "gui.h"
 #include "layout.h"
-#include "menu.h"
 #include "mix.h"
 #include "push2.h"
 #include "scale.h"