FE: Modify Consumer Lag default value when viewing Consumer List

Author: K-Diger

kafka-ui-react-app/src/components/ConsumerGroups/List.tsx

@@ -62,7 +62,7 @@ const List = () => {
         header: 'Consumer Lag',
         accessorKey: 'consumerLag',
         cell: (args) => {
-          return args.getValue() || 'N/A';
+          return args.getValue() || '0';
         },
       },
       {