When the user hits the last `Export...` button on the export modal, open a file output. Pre-fill the file name with the collection name and the file extension. Add an increasing number if the file name already exists in the default export location.

After the export file output has been chosen, start the export. If there's an error show it in the modal. 

If no errors were encountered initially then hide the modal and begin showing the progress toast.

https://www.figma.com/file/4sXj42XyicBsdQkYIugHaV/Compass-Import%2FExport?node-id=1134%3A47584&t=FoEPTv8iHfB487DG-1 

When the export is in progress and the toast is shown, use the progress callback responses from the export to show the amount of documents exported in the toast.

Show a `Cancel` action on the toast while the export is in progress. This should open a confirmation modal: https://www.figma.com/file/4sXj42XyicBsdQkYIugHaV/Compass-Import%2FExport?node-id=1452%3A48466&t=FoEPTv8iHfB487DG-1 

If an error occurs, change the variant to danger and show the error in the toast: https://www.figma.com/file/4sXj42XyicBsdQkYIugHaV/Compass-Import%2FExport?node-id=1304%3A48403&t=FoEPTv8iHfB487DG-1 

On export success, update the variant and make the action `View file` which opens the file in the file browser.

Designs: https://www.figma.com/file/4sXj42XyicBsdQkYIugHaV/Compass-Import%2FExport?node-id=1019%3A45601&t=FoEPTv8iHfB487DG-1