Publication Categories with no "Name" field cannot be filtered.

[Issa Mahasneh]

Describe the bug
If there is a Publication Category with an empty "Name" field, it appears within the categories' filter in the Pubications Page, however, when clicked, material under this category is not shown, as all the publications are shown.

To Reproduce
Steps to reproduce the behavior:

1. Create a new Publication Category, don't select a Name from the previously generated names list.
2. Navigate to the Publications Page.
3. Click the newly created category in the Categories' filter.
4. Add the new category to a new publication, or edit an existing publication.
5. All the content is displayed, rather than publications within the selected category.

Expected behavior
Only publications categorized within a category should be displayed.