theming fix

I've added the Audacious music player to Kubuntu 20.04, but when I started it up, it looked like this:

Not good. Toolbar buttons don't even show up. This is KDE Plasma 5.18.4. Under System Settings > Appearance, the Global Theme is set to Breeze Dark, as is the Plasma Style. Application Style is set to Breeze.

From the Application Style window, I clicked on the "Configure GNOME/GTK Application Style..." button down at the bottom of the window. In the next window, I could see that the GTK2 and GTK3 themes were set to Breeze, and there was a preview:

I changed the GTK2 and GTK3 themes to Breeze Dark:

Issue fixed: