[3.3.x] Settings: fix display in Chinese when region is China (mainland)

This removes the previous error prone and slow custom way of trying to find the correct language and region codes with consecutive read attempts of the files.

It is replaced by a lookup of the Settings.bundle and using the system API to just ask for the localized string, which will automatically return the correct result.

(cherry picked from commit 7354725c)

Backport of !673 (merged)