Make ScriptDatum in spending scripts optional in accordance with CIP-0069

[Jimbo4350]

Changelog

- description: |
    Make ScriptDatum in spending scripts optional in accordance with CIP-0069
# uncomment types applicable to the change:
  type:
  - feature        # introduces a new feature
  - compatible     # the API has changed but is non-breaking

Context

Additional context for the PR goes here. If the PR fixes a particular issue please provide a link to the issue.

How to trust this PR

Highlight important bits of the PR that will make the review faster. If there are commands the reviewer can run to observe the new behavior, describe them.

Checklist

• Commit sequence broadly makes sense and commits have useful messages
• New tests are added if needed and existing tests are updated. See Running tests for more details
• Self-reviewed the diff

[palas]

FYI: Because we now enforce the use of cabal-gild to format cabal files and, in order to reduce the amount of hassle, I have cherry-picked the appropriate commit into your PR. This will make the cabal-gild CI check pass for the PR. The commit should be discarded automatically as soon as you either rebase or merge the PR (since it is already in the main branch). Feel free to discard it if you want, but that will make the new required action to fail until you rebase.

[palas]

FYI: I have rebased your branch because we have done changes to the formatting. I have made a copy of the unrebased branch here: backup/jordan/make-v3-script-datum-optional