Update order status with processedAt type for customer account surface

[joshlbaker]

This PR adds the Order processedAt type to unstable for the customer-account surface.
The corresponding PR for passing this attribute to the Order API can be found here.

Background

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Solution

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🎩

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Checklist

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• I have updated relevant documentation

[github-actions]

We detected some changes in packages/*/package.json or packages/*/src, and there are no updates in the .changeset directory. If the changes are user-facing and should cause a version bump, run yarn changeset to track your changes and include them in the next release CHANGELOG. If you are making simple updates to repo configuration, examples, or documentation, you do not need to add a changeset.

[joshlbaker]

Closing as this work was included here