With wikibase/javascript-api turned into a "stand-alone" wikibase-api npm package, it is no longer needed to run all extension jobs on Jenkins. npm install and npm test will be just fine. It is no longer an extension basically.
Note that CI config should probably only be changed after QUnit tests are part of "npm test" script, i.e. earliest after https://gerrit.wikimedia.org/r/384012 got merged.