Make list-selected chords play preview sounds

Follow-up from this request: https://github.com/musescore/MuseScore/issues/19940

Task

Double-clicking a single note to list-select its entire chord plays a preview sound of only the clicked note on both clicks. On the second click, it should play a preview sound of the entire chord to accurately represent what's now selected.

Similarly, when a list-selected chord is repeated via the 'Repeat selection' command (shortcut R) when in normal mode, it should play that chord like any other note preview. This already happens when using R in note input mode, so we should match the behavior in normal mode.

• Note: We don't do this for range selections currently because if the range selection contains multiple notes/chords at different beat positions, obviously it doesn't make sense to just play the first one. So it's not necessary to change the range selection note preview behavior.

In Preferences -> Note input -> Note preview, the 'Hear playback when adding, editing, and selecting notes' toggle should still be obeyed. The 'Play chord when editing' sub-option should have no effect on this since it has to do with note input mode.