chore: Refactor test by reusing a variable

[lym953]

What does this PR do?

The variable stateMachineName is defined with the same value in every test case, so let's extract it out to reduce some code.

Motivation

Testing Guidelines

npm test

Additional Notes

Types of changes

• [ ] Bug fix
• [ ] New feature
• [ ] Breaking change
• [x] Misc (docs, refactoring, dependency upgrade, etc.)

Check all that apply

• [x] This PR's description is comprehensive
• [ ] This PR contains breaking changes that are documented in the description
• [ ] This PR introduces new APIs or parameters that are documented and unlikely to change in the foreseeable future
• [ ] This PR impacts documentation, and it has been updated (or a ticket has been logged)
• [x] This PR's changes are covered by the automated tests
• [ ] This PR collects user input/sensitive content into Datadog

[lym953]

/merge

[dd-devflow[bot]]

:steam_locomotive: MergeQueue: pull request added to the queue

The median merge time in main is 2m.

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