center headings in work listed in dashboard.

[blancoj]

Fixes #3721

This PR address the headers and values listed on the dashboard for works. Many values were not centered.

Guidance for testing, such as acceptance criteria or new user interface behaviors:

• Go to dashboard/my/works page
• Verify that the headers of the table and values are centered, with the exception of the 1st 2 columns
• Got to dashboard/works page
• Verify that the headers of the table and values are centered, with the exception of the 1st 2 columns

@samvera/hyrax-code-reviewers

[ghost]

@blancoj the change looks fine, but the tests have failed with

1) Sending an email via the contact form sends mail
     Failure/Error: <%= render_thumbnail_tag(recent_document, {width: 90}, {suppress_link: true}) + recent_document.to_s %>

I can't see how that would be related, but it needs to pass before we can merge.

I'll try a re-run of circleci in case that fixes it.