[Open data] Update reservation recommendations dataset example

[flanakin]

⚠️ Problem

Cost Management reservation recommendation exports changed format.

🛠️ Solution

Update the sample dataset file to cover the new format.

ℹ️ Additional context

Confirm their change is staying before making this change. If they revert it (which they should) then we will need to revert this as well.

🙋‍♀️ Ask for the community

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