Vulnerability report does not show skeleton loader when filters are changed and the list is loading new data

Summary

When viewing a project's vulnerability report, a list of vulnerabilities is shown:

When the filters for the report are changed (the dropdowns above the list), the list is supposed to show a skeleton loader to indicate that it's currently loading new data. However, the skeleton loader does not show and the old list will remain visible until the new data finishes loading and replaces it.

On large projects with lots of vulnerabilities, it can take several seconds to load the new data. As a result, to the user it appears as if changing the filters did not do anything, when in actuality the data is being loaded in the background.

Steps to reproduce

1. Go to a project's vulnerability report, i.e. https://gitlab.com/gitlab-examples/security/security-reports/-/security/vulnerability_report
2. Change one of the filters using the dropdowns above the vulnerability list.
3. Observe that the vulnerability list does not show a skeleton loader. If the data is loading too fast, you can use Chrome Devtools' Network Conditions feature to artificially slow it down:

What is the current bug behavior?

Vulnerability list still shows old results while new data is fetched in the background

What is the expected correct behavior?

Vulnerability list shows skeleton loader when filter is changed