The job was failing with `301 Moved Permanently`. The problem was that
`mediawiki_url` was not `https` and was missing `www`.
Bug: T128079
Change-Id: I4f142c4ed17826b1e4051846395940e139e47689
We used to rely on the env variable BROWSER_USERAGENT for tests
requiring a customer user agent. 2c3ac55a6 got rid of it in favor of
loading the :browser_useragent from environments.yml where it has not
been set. That in turns caused tests to fail with:
"missing configuration for browser_useragent"
Set browser_useragent to 'test-user-agent' in the environments.yml
Also drop unused test2 env and add mediawiki-org
Bug: T128064
Change-Id: I720d590505dd5e30c6e9435de456563b8d36f9ea