The ability to break chorus plants with arrows is a new feature of 1.14, and it doesn't trigger any kind of event that I can find. I checked BlockBreakEvent, BlockExplodeEvent, BlockFadeEvent, BlockDamageEvent, and EntityChangeBlockEvent. The suppose the most logical event for it to trigger is EntityChangeBlockEvent, since you have an Entity (arrow) changing a block (chorus plant).

I develop a block protection plugin, and without this event I can't stop players from destroying chorus plant blocks with bows on a protected plot. Thanks!