This is a bug. Steps to reproduce:
1: Have ears.
2: Click "Play"
3: Click your deck so that the tutorial fairy appears and makes noise until you close Arena.
4: Enter Queue, Start a Game, End a Game, Re-enter Queue without opening the list of decks, slam your head against a wall, nothing short of closing Arena will get rid of the fairy noise. As it is on the main audio track (SFX) you will not be able to play the game as you will be annoyed the entire time.
5: Marvel at how Wizards could allow such an annoying bug to exist on the digital platform they've been pushing, for months, if not years.
I am on Windows.
Experienced results: Infinite annoyance at the pervasive noise which never goes away.
Expected results: As soon as that fairy is off the screen the noise it makes should cease to exist. Better yet, make the fairy mutable. Have it be its own audio slider that I can set to 0 and never listen to again. Even better, have an option to get rid of it completely and irrevocably.