Speaker test available even if no device in the list

Linux Omen 4.15.0-54-generic 58-Ubuntu SMP Mon Jun 24 10:55:24 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux

I resumed the laptop and pulseaudio broke. My journal was full of:

[pulseaudio] protocol-native.c: Warning! Too many connections (64), dropping incoming connection.

Test popover is actually clickable but only the blue/white icon is shown and it doesn't disappear nor do anything. I suggest to make it enable only if at least one device is selected in the list above.

Bug similar to https://github.com/elementary/switchboard-plug-sound/issues/67