Fix json issues (#5865)

web/pgadmin/browser/server_groups/servers/databases/schemas/tables/columns/__init__.py

@@ -374,7 +374,10 @@ class ColumnsView(PGChildNodeView, DataTypeReader):
             if k in ('description',):
                 data[k] = v
             else:
-                data[k] = json.loads(v, cls=ColParamsJSONDecoder)
+                try:
+                    data[k] = json.loads(v, cls=ColParamsJSONDecoder)
+                except TypeError:
+                    data[k] = v
 
         required_args = {
             'name': 'Name',