Add sound preview to debate setup

[Mateusz-Dobrzynski]

In debate setup view, there's no easy way to test round effects. It should be changed.

TO-DO:

• Add two buttons labeled "Protected time" and "Speech end" to the right of the "Bell sounds" label,
• Move the sound pack dropdown below the "Bell sounds" label to make room for the buttons.

How to test:

• Ensure that buttons exist and can be clicked,
• Listen for play event.

References:

• Playwright: waiting for events,
• play event.

[jakubmanczak]

I feel like it putting it there might be a bit distracting for some, and it will only serve to clutter the already large and confusing debate config UI for any user who had already pressed it. Perhaps, if the sounds aren't the stock selection, a simple link to the sound preview page would suffice?