Add Tuplet dialog - WYSIWYG preview

[bebobebo]

When adding long (9+) tuplets - "Other" - it would be helpful to have a preview of the output note pattern shown in the dialog (below) so that if I've made any arithmetic error in calculating whether I need 1/4,1/8,... notes over the selected range it can be adjusted before hitting OK.

Otherwise it's an awkward re-navigation of the menu Add > Tuplets > Other... to do it over.

Also: I don't seem to be able to set up a shortcut key for this dialog, which is desirable in scores that are heavy in tuplets of different lengths.

Discussed at: https://musescore.org/en/comment/1290748#comment-1290748
Suggestion for how this might look (except with notes rather than rests)