Collection show page does not show thumbnail

[elrayle]

Descriptive summary

If an image has been selected to serve as the thumbnail for a collection, then the thumbnail should be visible in the descriptive metadata area of the public show page for the collection.

Rationale

A selected thumbnail is expected to be visible to users.

Expected behavior

The thumbnail should appear above the Collection Details on the show page.

Actual behavior

The thumbnail does not appear on the show page.

Steps to reproduce the behavior

1. Create a public collection
2. Create a public work that includes an image file
3. Put the work in the collection
4. Edit the collection and select the work's image as the thumbnail for the collection
5. Navigate to the collection's public show page

Confirm that the thumbnail is visible over the Collection Details.

Related work

Issue #3164 - Collection Thumbnails don't show in search results
Issue #3319 - Select thubmail image for collection only shows 10 files in dropdown
Issue #2008 - Adding a thumbnail to a collection does not change the thumbnail in search results