Fix failure handler inheriting config

[jpwilliams]

Summary

Failure handlers incorrectly inherit config from their parent function.

Checklist

• [ ] ~Added a docs PR that references this PR~ N/A
• [ ] ~Added unit/integration tests~ N/A
• [ ] Added changesets if applicable

[changeset-bot[bot]]

🦋 Changeset detected

Latest commit: bb22c3af8982473251995ed96088e0f60b8ebf21

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

| Name | Type | | ------- | ----- | | inngest | Patch |

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[jpwilliams]

Closing in favour of #630, as that also requires this change and is a bit messy to rebase due to the cross-repo fun.