Update src/rpc/governance.cpp

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

Author: knst

src/rpc/governance.cpp

@@ -730,7 +730,7 @@ static RPCHelpMan gobject_list_helper(const bool make_a_diff)
                 },
             },
             RPCResult{"if request is invalid",
-                RPCResult::Type::STR_HEX, "", "Error string"
+                RPCResult::Type::STR, "", "Error string"
             },
         },
         RPCExamples{""},