Add directional characters to match string in test_settings_change_language.py

Add directional formatting characters into the match string so that Python can match them.
Marionette does not yet remove these however I have filed https://bugzilla.mozilla.org/show_bug.cgi?id=883555 to discuss the correct handling of them.

`master` -> Merge
`v1-train` -> Do not merge (will break build)
`v1.0.1` -> Do not merge (will break build)