kcm/regionandlang: fix Setting LANG to C mangles preview strings

BUG: 482234

We return locale name if locale's native name is empty.


(cherry picked from commit b7a00653)

29e50b24 kcm_regionandlang: fix Setting LANG to C mangles preview strings
810ef65c Apply 1 suggestion(s) to 1 file(s)