UI: Center vertical volume control buttons

The mute and config buttons were not vertically centered.

UI/volume-control.cpp

@@ -301,12 +301,15 @@ VolControl::VolControl(OBSSource source_, bool showConfig, bool vertical)
 		controlLayout->setContentsMargins(0, 0, 0, 0);
 		controlLayout->setSpacing(0);
 
-		if (showConfig)
+		if (showConfig) {
 			controlLayout->addWidget(config);
+			controlLayout->setAlignment(config, Qt::AlignVCenter);
+		}
 
 		controlLayout->addItem(new QSpacerItem(3, 0));
 		// Add Headphone (audio monitoring) widget here
 		controlLayout->addWidget(mute);
+		controlLayout->setAlignment(mute, Qt::AlignVCenter);
 
 		meterLayout->setContentsMargins(0, 0, 0, 0);
 		meterLayout->setSpacing(0);