Apparently NixOS didn't have Python (sometimes!) so let's not assume.
By reusing the JSON "parsing" code from cowsay, we can self-disable
to handle this case.
Reported-by: Shahana Farooqui <shahana.farooqui@gmail.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Changelog-Fixed: Plugins: `clnrest` now correctly self-disables if Python not present at all.