Deprecate GHC.JS.Prim.Internal.Build (#23432)

See https://github.com/haskell/core-libraries-committee/issues/329

Please take a few moments to address the following points:

• if your MR touches base (or touches parts of ghc-internal used or re-exported by base) more substantially than just amending comments or documentation, you likely need to raise a CLC proposal before merging it.
• if your MR may break existing programs (e.g. causes the compiler to reject programs), please describe the expected breakage and add the user-facing label. This will run ghc/head.hackage> to characterise the effect of your change on Hackage.
• ensure that your commits are either individually buildable or squashed
• ensure that your commit messages describe what they do (referring to tickets using #NNNN syntax when appropriate)
• have added source comments describing your change. For larger changes you likely should add a Note and cross-reference it from the relevant places.
• add a testcase to the testsuite.
• updates the users guide if applicable
• mentions new features in the release notes for the next release

If you have any questions don't hesitate to open your merge request and inquire in a comment. If your patch isn't quite done yet please do add prefix your MR title with WIP:.

By default a minimal validation pipeline is run on each merge request, the full-ci label can be applied to perform additional validation checks if your MR affects a more unusual configuration.

Once your change is ready please remove the WIP: tag and wait for review. If no one has offered a review in a few days then please leave a comment mentioning @triagers and apply the Blocked on Review label.