WIP: Visually even-out headings on Integrations Settings pages

What does this MR do?

What are the relevant issue numbers?

From https://gitlab.com/gitlab-org/gitlab-ee/issues/9258#note_132429317

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Tested in all supported browsers
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• EE specific content should be in the top level /ee folder