output/PipeWire: check SPA_PROP_channelVolumes, not control name

Since PipeWire 0.3.53, there is no control name anymore, therefore the
name check doesn't work anymore, breaking volume change events.

This obsoletes the crash bug fix in commit 2ee57f9b0d

src/output/plugins/PipeWireOutputPlugin.cxx

@@ -236,9 +236,11 @@ private:
 
 	void ControlInfo([[maybe_unused]] uint32_t id,
 			 const struct pw_stream_control &control) noexcept {
-		if (control.name != nullptr &&
-		    StringIsEqual(control.name, "Channel Volumes"))
+		switch (id) {
+		case SPA_PROP_channelVolumes:
 			OnChannelVolumes(control);
+			break;
+		}
 	}
 
 	static void ControlInfo(void *data, uint32_t id,