Accessibility Issue with zooming in on default thumbnail images.

[tdonohue]

trafficstars

Describe the bug

Default thumbnail wording breaks when zooming in. Tested in Chrome, Firefox and Edge. Occurs in DSpace version 8.x and 7.x

This occurs on every page that has the "No Thumbnail Available" image.

To Reproduce

Steps to reproduce the behavior:

1. Go to Demo Site homepage.
2. Start at 100% (default) zoom.
3. Zoom in to 175% and notice the thumbnail wording breaks the box.

Expected behavior

The thumbnail wording should not break out of the box.