Add E2E tests for the new frontend language selection flow

As of #558 we have a new standard way for users to select language: we should add a few E2E tests to validate the more common scenarios, such as:

The impact of Browser/OS language
Selecting language in the dropdown while not logged in...
... and then logging in
Changing language while logged in...
... then log out
Change the language in Profile and/or Account
Make sure changing the language in any given place has the appropriate effect in the other selection dropdowns

Some of this is hand-wavy: when writing the tests, investigate what the proper behavior should be.

Navigation Menu