Fix vulnerability comment delete button spinner position

What does this MR do?

When viewing the vulnerability details for a vulnerability on the security dashboard:

If there's a comment on a history item at the bottom, a delete button is shown to delete the comment. Clicking on the button shows two confirmation buttons:

And when the delete button is clicked, a loading spinner is shown on the button, but is positioned incorrectly. This MR fixes that:

Before	After

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• [-] Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• [-] Database guides
• [-] Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers
• [-] Informed Infrastructure department of a default or new setting change, if applicable per definition of done