[Cloud Posture]fix incorrect vuln_mgmt details in flyout (#157745)

## Summary

Summarize your PR. If it involves visual changes include a screenshot or
gif.
Currently, after navigating any page after the first page and clicking
on vulnerability, the flyout displays incorrect details.

Currently, we use the `data.page`, which lists the maximum amount of
vulnerabilities(500 vulnerabilities). The `vulnerabilityIndex` is set
each time, a user clicks to expand vulnerability. We were currently only
selecting vulnerabilities from the first page.

Solution:

Use `slicedPage` to get the vulnerabilities on the current page and then
select vulnerability by `vulnerabilityIndex`


https://github.com/elastic/kibana/assets/17135495/df682ecf-d024-45e4-84ca-d7df22a60ec4

x-pack/plugins/cloud_security_posture/public/pages/vulnerabilities/vulnerabilities.tsx

@@ -116,7 +116,10 @@ const VulnerabilitiesContent = ({ dataView }: { dataView: DataView }) => {
   const slicedPage = usePageSlice(data?.page, pageIndex, pageSize);
 
   const invalidIndex = -1;
-  const selectedVulnerability = data?.page[urlQuery.vulnerabilityIndex];
+
+  const selectedVulnerability = useMemo(() => {
+    return slicedPage[urlQuery.vulnerabilityIndex];
+  }, [slicedPage, urlQuery.vulnerabilityIndex]);
 
   const onCloseFlyout = () => {
     setUrlQuery({