Report errors on dbus interfaces
We should use g_dbus_method_invocation_return_error()
in rename_file_on_finished()
if an error occurs and similarly in other functions, and only call *_complete if it was successful.
However, a timeout could occur on the call given that some operations take more than the default 25 seconds timeout for a dbus call to complete.
For this, since the dbus API is intended to only be consumed by desktop-icons extension, we would need easy handling on the gjs to modify the timeout. A request like gjs#122 (closed) would be appropiate.