ci: Enable classic mode

Everything is worth testing.
2 jobs for ci-test in 40 seconds
latest
Status Job ID Name Coverage
  Source Check
passed #217121
eslint

00:00:23

 
  Build
failed #217122
build-shell-extensions

00:00:17

 
Name Stage Failure
failed
build-shell-extensions Build
Build machine cpu family: x86_64
Build machine cpu: x86_64
Program js60 found: YES (/usr/bin/js60)
Program sassc found: NO

meson.build:90:2: ERROR: Program(s) ['sassc'] not found or not executable

A full log can be found at /builds/GNOME/gnome-shell-extensions/_build/meson-logs/meson-log.txt
ERROR: Job failed: exit code 1