Getting rid of "SoX is using the microphone" icon

I installed and ran EasyEffects from a flatpak (on KDE), and since then, I have a “SoX is using the microphone” icon in the tray bar:

I quit the application that used it, but the icon remains. It also shows SoX in input and output streams.

Is there a way to get rid of them, without rebooting?