We tried to repro the issue with the manifest file provided and faced similar errors.
When clicking "Preview in Teams" button, it opens up a dialog which says, "Manifest parsing has failed" and when I close the dialog it shows a message in the developer portal "App does not have the required permissions for this operation".
We have raised a bug for the same and engineering team is looking into it. We will inform you once we get any further update.
Thanks,
Prasad Das
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