[test/fix] prevent FirefoxHelper from silently failing to start
This was breaking some tests without any obvious error message and you should
fail as early as possible to make debugging easier.
Closes #17260390
missing-dep-for-interpreter make => make | build-essential | dpkg-dev (usr/*/cubicweb/skeleton/debian/rules)
embedded-javascript-library usr/share/cubicweb/cubes/shared/data/jquery.js