Steps to reproduce:

• setup your browser to French
• load AdminUI
• Login
• wait for the profiler
• click on the translation tab

Results:
Symfony Locale is set to `en_GB`
Native Translation mechanism of Symfony is not working.
" |trans" uses the en translation file all the time (in Admin UI)

Expected Result:
Symfony Locale is set to `fr_FR`
Native Translation mechanism of Symfony must be working.
" |trans" uses the fr translation file all the time (in Admin UI)

Thanks