Remove "Account administration pages" language selection for now

The langue selection based on "Account administration pages" does not work. They are major issues opened for years that make this feature useless.

Until they are fixed, I think this option should be removed from the interface or at least provide a "testing feature, use at your own risk".

Perhaps running all test with this feature enable and check if interface language and content language is correct and the actual test pass would be a good start.