Remove duplicate key in stale workflow

[kiftio]

What changes are you making?

Remove duplicate key in workflow Use stale label for PRs and issues

N.B. my IDE did some autoformatting, probably best to hide whitespace when reviewing

How to test

n/a

Before you merge

[!IMPORTANT]

• [ ] I've added tests to support my implementation
• [x] I have read and agree with the Contribution Guidelines.
• [x] I have read and agree with the Code of Conduct.
• [ ] I've updated the README.

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Checklist for releasing a new version

- [ ] I have bumped the version number in the [`build.gradle` file](https://github.com/Shopify/checkout-kit-android/blob/main/lib/build.gradle#L17) - [ ] I have added a [Changelog](https://github.com/shopify/checkout-sheet-kit-android/blob/main/CHANGELOG.md) entry.

[!TIP] See the Contributing documentation for instructions on how to publish a new version of the library.