base: Explicit dependency to workaround #24436

Currently `ghc -M` fails to account for `.hs-boot` files correctly,
leading to issues with cross-package one-shot builds failing. This
currently manifests in `GHC.Exception` due to the boot file for
`GHC.Internal.Stack`. Work around this by adding an explicit `import`,
ensuring that `GHC.Internal.Stack` is built before `GHC.Exception`.

See #24436.