Update supplemental datum script to use findDatum

[Jimbo4350]

Description

Add your description here, if it fixes a particular issue please provide a
link
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Checklist

• Commit sequence broadly makes sense and commits have useful messages
• New tests are added if needed and existing tests are updated. These may include:
  • golden tests
  • property tests
  • roundtrip tests
  • integration tests
    See Runnings tests for more details
• Any changes are noted in the CHANGELOG.md for affected package
• The version bounds in .cabal files are updated
• CI passes. See note on CI. The following CI checks are required:
  • Code is linted with hlint. See .github/workflows/check-hlint.yml to get the hlint version
  • Code is formatted with stylish-haskell. See .github/workflows/stylish-haskell.yml to get the stylish-haskell version
  • Code builds on Linux, MacOS and Windows for ghc-8.10.7 and ghc-9.2.7
• Self-reviewed the diff

Note on CI

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You will need to get someone with write privileges. Please contact IOG node developers to do this
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[carbolymer]

Suggested change

	> cardano-cli transaction hash-script-data --script-data-value 1 :( 1 24-10-30 - 11:48:29
	> cardano-cli transaction hash-script-data --script-data-value 1

I think this bit isn't needed?