Steps:
- Add additional browser test job to run the browsertests in Wikibase.
- Move test that only depend on one wiki with Wikibase and not something else from the Wikidata build into Wikibase
- while deleting them from WikidataBrowserTests.git
- while rewriting parts that require being logged in to use user_factory
- while rewriting parts that use ENVs from tests/browser/features/support/env.rb to use MediawikiSelenium::Environment instead
- while rewriting parts that rely on existing content in the Wiki to use ruby to create the fixture
Things to consider afterwards:
- It would definitely be nice to have some of the browsertests removed by covering these cases in QUnit or PHPUnit if possible. See T118283.
- Enable some to run during gate-and-submit (before merge) by adding the correct `@group` tag.