Use the fallback description if the backend server description is null

This is technically incorrect but it seems like this is the best we can do...

proxy/src/main/java/com/velocitypowered/proxy/connection/client/StatusSessionHandler.java

@@ -120,6 +120,10 @@ public class StatusSessionHandler implements MinecraftSessionHandler {
               continue;
             }
 
+            if (response.getDescriptionComponent() == null) {
+              continue;
+            }
+
             return new ServerPing(
                 fallback.getVersion(),
                 fallback.getPlayers().orElse(null),