Add GHC 9.6.1-alpha1 to github CI

[Mikolaj]

This depends on or is related to the following:

#7798
#8630
#8451
#8504

[Mikolaj]

Also, copying from #hackage:

also, we'd ideally make CI support GHC 9.6(alpha) and then there will be a lot of CI failures to fix, because we have lots of isGHC9.4 in tests, most of which should probably be changed to isGHC>=9.4
wow, a lot of our tests are disabled for newer GHCs due to unknown heisenbugs, some of which are surely due to github CI vagaries, but not all

[Mikolaj]

This is successfully done in #8754. Closing.