Refresh vulnerability state and timestamp when changed by other user

What does this MR do?

On the standalone vulnerability page, if user A is looking at the page while user B changes the vulnerability state, user A does not see the change until they refresh the page. This MR fixes that by updating the state for user A while they are looking at the page, without needing a refresh:

Peek_2020-06-18_23-35

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