Currently Content Type Translate is not used based on user's browser settings, but is based on the selected language instead.
1. Given a Content Type translated into French and Polish languages
2. Given an user using browser in Polish language
3. When editing a Content Item (of that translated Content Type) in French language
4. Then Content Type field labels are displayed in Polish language
4. Then Content Type field labels are displayed in French language
This can result in mixed AdminUI languages - Polish for some labels and French for Content Type field labels