parse sub channel data on GET api

src/server/controllers/guild/sub.api.controller.ts

@@ -69,7 +69,10 @@ export const get = async (request: Request, response: Response) => {
             return;
         }
 
-        data.channels = JSON.parse(data.channels);
+        // Parse empty channel arrays
+        data.channels = data.channels === "[null]"
+            ? []
+            : JSON.parse(data.channels);
 
         response.json(data);
     }