main: Make the style init priority super high

This ensures we load the styles before any window appears.

Fixes Librem5/libhandy#214.
11 jobs for style-loading in 23 minutes and 4 seconds (queued for 5 minutes and 47 seconds)
Status Job ID Name Coverage
  Build
passed #252396
librem5
api-visibility

00:02:49

passed #252398
librem5
build-debian-clang

00:04:14

passed #252397
librem5
build-debian-gcc

00:03:18

passed #252399
librem5
build-fedora-gcc

00:03:19

 
  Test+Docs
passed #252400
librem5
build-gtkdoc

00:03:13

passed #252401
librem5
unit-test

00:03:19

41.7%
 
  Package
passed #252402
librem5
package-debian-buster

00:03:23

passed #252403
librem5:arm64
package-debian-buster:arm64

00:05:54

passed #252404
flatpak
package-flatpak

00:01:31

 
  Test Package
passed #252405
librem5
autopkgtest-debian-buster-package

00:02:59

passed #252406
librem5
lintian-debian-buster-package

00:01:09