Use v-safe-html for vulnerability history comment

What does this MR do?

When viewing an individual vulnerability on the security dashboard, if there is a vulnerability history entry, the user can type in a comment for it:

Previously, the comment was shown using v-html. This MR changes it to use v-safe-html instead.

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