kcms/soundtheme: Shorten preview label
Shorten the "Preview sounds:" label to just "Preview:".
This is enough given the context, and helps to avoid longer string on some languages which could get elided.
Follow-up from !3917 (merged) for 6.1
Shorten the "Preview sounds:" label to just "Preview:".
This is enough given the context, and helps to avoid longer string on some languages which could get elided.
Follow-up from !3917 (merged) for 6.1