System language handling in tours and plugin manager

1. install musescore on a computer whose system language we shall refer to as language A ("Chinese")
2. choose the application language to be another preferred language, referred to as language B ("English")
3. trigger a popup window for tours or the plugin manager.

the languages will be inconsistent, with parts being in language A and parts in language B.
the window will have some aspects in the system language and some aspects in the application language.

(new user here, after poking around those were the only instances of this happening that I found so far, which is interesting)