System info: Remove empty parentheses when video adapter driver name is unknown

Seems to be the case at least for me on Fedora, and in various issues I see from
other Linux users.

editor/editor_node.cpp

@@ -4928,7 +4928,7 @@ String EditorNode::_get_system_info() const {
 		const String &vad_version = video_adapter_driver_info[1]; // Version could be potentially empty on Linux/BSD.
 		if (!vad_version.is_empty()) {
 			graphics += vformat(" (%s; %s)", vad_name, vad_version);
-		} else {
+		} else if (!vad_name.is_empty()) {
 			graphics += vformat(" (%s)", vad_name);
 		}
 	}