Download button rendering on item page does not label Primary bitstream

[lgeggleston]

Describe the bug

On an item page with simple links for file download, a "Primary" badge is added next to a primary file/bitstream when applicable (see also documentation). However when the item page uses the new Download button component display, there's no badge and therefore no way for the user to see which is the primary file.

Observed on sandbox (10.0) while configured to use the new Download component.

To Reproduce

Steps to reproduce the behavior:

1. Deposit or go to the item page of an item with a primary bitstream set. (If submitting the item, add multiple files and check the "Primary" box for one of them)
2. In config, make sure showDownloadLinkAsAttachment is set to true so the Download component is used
3. Go to the item page
4. There's no indication of which file you set as primary

Expected behavior

The primary badge is displayed on the Download button component, or the information is clearly designated to the user in a similar way.

Related work

New component was added in: #5132