Recent AD woes

* [ ] Figure out what about ChainRules 1.0 broke AD https://github.com/marius311/CMBLensing.jl/runs/3303656637#step:6:750
* [ ] Figure out why this takes forever `@time gradient(f -> norm(unmix(f,ϕ,(;),ds)[1]), f)` (or merge PPL which seems unaffected)