Accept packages with `mhs-options` (MicroHs options)

[sol]

Uploading my package to Hackage failed due to mhs-options:

https://github.com/hspec/hspec/actions/runs/20167421952/job/57894166588

This is a blocker for me as without these options my package does not build with MicroHs.

Also note that cabal check only warns on mhs-options, it does not fail with "Hackage would reject this package".

[ysangkok]

I think this is blocked on Cabal getting proper support for this:

• Don't warn on mhs-options (MicroHs options) cabal#11341