Add reactive vulnerability status description

What does this MR do?

This MR makes the vulnerability status description update client-side when the vulnerability state changes. The vulnerability state is changed through a dropdown on the right side of the header:

Screenshot

Note that this MR is only for the vulnerability status description:

Vulnerability status description

When the vulnerability status is "detected", the pipeline link is shown:

Description parts

When the vulnerability status is anything else, the user avatar for the user that changed that status is shown:

Description parts

When the vulnerability state is changed from the dropdown, an API request is made and a new vulnerability object is returned. While this request is being made, a skeleton loader is shown:

Skeleton loader

The vulnerability data only has the user ID; a separate request needs to be made to get the actual user info. While this request is being made, a separate loader is shown for the user avatar only:

User avatar loader

How to test locally

https://gitlab.com/snippets/1956676

Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry Currently behind feature flag, no changelog needed
• [-] 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

Related issue: #196725 (closed)