[Cloud Security] do not filter out CNVM documents with missing or unk…

…nown severity (elastic#163419)

## Summary

This PR removes filtering vulnerabilities where the `severity` field is
missing or is different from CRITICAL, HIGH, MEDIUM or LOW. Right now
this is handled ok in the data grid but won't be reflected in the
severity map or trend chart components.
<img width="1728" alt="Screenshot 2023-08-08 at 17 42 46"
src="https://github.com/elastic/kibana/assets/478762/45ccf860-0cb7-4b03-ab51-5720dd7f90f9">



fixes
- elastic/security-team#7289

x-pack/plugins/cloud_security_posture/common/utils/get_safe_vulnerabilities_query_filter.ts

@@ -5,28 +5,15 @@
  * 2.0.
  */
 import { QueryDslQueryContainer } from '@elastic/elasticsearch/lib/api/types';
-import { VULNERABILITIES_SEVERITY } from '../constants';
 
 export const getSafeVulnerabilitiesQueryFilter = (query?: QueryDslQueryContainer) => ({
   ...query,
   bool: {
     ...query?.bool,
     filter: [
       ...((query?.bool?.filter as []) || []),
-      {
-        bool: {
-          minimum_should_match: 1,
-          should: [
-            { match_phrase: { 'vulnerability.severity': VULNERABILITIES_SEVERITY.CRITICAL } },
-            { match_phrase: { 'vulnerability.severity': VULNERABILITIES_SEVERITY.HIGH } },
-            { match_phrase: { 'vulnerability.severity': VULNERABILITIES_SEVERITY.MEDIUM } },
-            { match_phrase: { 'vulnerability.severity': VULNERABILITIES_SEVERITY.LOW } },
-          ],
-        },
-      },
       { exists: { field: 'vulnerability.score.base' } },
       { exists: { field: 'vulnerability.score.version' } },
-      { exists: { field: 'vulnerability.severity' } },
       { exists: { field: 'resource.id' } },
       { exists: { field: 'resource.name' } },
     ],

x-pack/plugins/cloud_security_posture/public/pages/vulnerabilities/utils/custom_sort_script.ts

@@ -28,13 +28,13 @@ export const severitySortScript = (direction: string) => ({
     script: {
       lang: 'painless',
       inline:
-        "if(params.scores.containsKey(doc['vulnerability.severity'].value)) { return params.scores[doc['vulnerability.severity'].value];} return 1000;",
+        "if(doc.containsKey('vulnerability.severity') && !doc['vulnerability.severity'].empty && doc['vulnerability.severity'].size()!=0 && doc['vulnerability.severity'].value!=null && params.scores.containsKey(doc['vulnerability.severity'].value)) { return params.scores[doc['vulnerability.severity'].value];} return 0;",
       params: {
         scores: {
-          LOW: 0,
-          MEDIUM: 1,
-          HIGH: 2,
-          CRITICAL: 3,
+          LOW: 1,
+          MEDIUM: 2,
+          HIGH: 3,
+          CRITICAL: 4,
         },
       },
     },