Make Error play better with ExceptionContext from GHC 9.12

[arybczak]

While Effectful.Exception is now compatible with changes to exception handling made in 9.12, Error is not.

Looks like this will require a little bit of a breaking change (the CallStack parameter in all functions will need to be changed to opaque ErrorContext or something) :(

[arybczak]

Considering regressions in the 9.12 series (in particular https://gitlab.haskell.org/ghc/ghc/-/issues/25529 and https://gitlab.haskell.org/ghc/ghc/-/issues/25883) this is not getting done in the next few months.

I will get to it once 9.12.3 is near its release.