[hotfix][ci] Bump github-script to v9 in action.yml

[snuyanzin]

What is the purpose of the change

The PR bumps github-script to v9 to fix warnings like at https://github.com/apache/flink/actions/runs/31820639896

Brief change log

GHA

Verifying this change

GHA warnings

Does this pull request potentially affect one of the following parts:

• Dependencies (does it add or upgrade a dependency): (yes)
• The public API, i.e., is any changed class annotated with @Public(Evolving): (no)
• The serializers: ( no)
• The runtime per-record code paths (performance sensitive): (no )
• Anything that affects deployment or recovery: JobManager (and its components), Checkpointing, Kubernetes/Yarn, ZooKeeper: ( no )
• The S3 file system connector: (no )

Documentation

• Does this pull request introduce a new feature? ( no)
• If yes, how is the feature documented? (not applicable)

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CI report:

• abd2fe4 Azure: SUCCESS

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