[UX] Use play/pause/stop icons instead of words with the musicbox messages

[yahiheb]

Press Play to start Looking at that message I am immediately looking for a button that literally says Play but there is none.
This could be a bit confusing for some users, so using icons would improve the UX here.

Master:

Proposal:

[yahiheb]

@wieslawsoltes I remember seeing you playing with icons inside of texts before is this possible and easy to do?

[SuperJMN]

@wieslawsoltes I remember seeing you playing with icons inside of texts before is this possible and easy to do?

From a purely GUI perspective, it's way easy. The problem is that our design currently supports messages that are non-formatted text.
Let me figure out something :)

[yahiheb]

Reopening this after #12507 reverted using in-lines.