testsuite Setup.hs pragma to test for Cabal 3.16 does not work as expected.

[MangoIV]

When trying to build locally using cabal-install 3.16 the pragma still evaluates to a version prior to 3.16 which makes the Setup.hs script not type check.

cabal list --installed | rg Cabal -A4
* Cabal
    Synopsis: A framework for packaging Haskell software
    Default available version: 3.16.1.0
    Installed versions: 3.14.1.0
    Homepage: http://www.haskell.org/cabal/
--
* Cabal-syntax
    Synopsis: A library for working with .cabal files
    Default available version: 3.16.1.0
    Installed versions: 3.14.1.0
    Homepage: http://www.haskell.org/cabal/

I assume this is because the Installed versions: is 3.14.1.0 shipping with 9.12.2 being used to evaluate the pragma but then the program itself is built with version 3.16? I assume this is a cabal bug in general but since Setup.hs builds are generally awful, I would be happy to instead get rid of Setup.hs I have seen the issue wrt build-tool-depends and I assume that we can get rid of the Setup.hs when that is resolved.

I am mainly leaving this here to track that.