[Cases] severity field in the cases list and allow to filter by it

x-pack/test/cases_api_integration/security_and_spaces/tests/common/cases/find_cases.ts

@@ -845,6 +845,22 @@ export default ({ getService }: FtrProviderContext): void => {
           // Only security solution cases are being returned
           ensureSavedObjectIsAuthorized(res.cases, 1, ['securitySolutionFixture']);
         });
+
+        it('should respect the owner filter when using range queries', async () => {
+          const res = await findCases({
+            supertest: supertestWithoutAuth,
+            query: {
+              severity: CaseSeverity.LOW,
+            },
+            auth: {
+              user: secOnly,
+              space: 'space1',
+            },
+          });
+
+          // Only security solution cases are being returned
+          ensureSavedObjectIsAuthorized(res.cases, 2, ['securitySolutionFixture']);
+        });
       });
     });
   });

x-pack/test/functional/fixtures/kbn_archiver/cases/8.2.0/cases_various_dates.json

@@ -20,6 +20,7 @@
       "syncAlerts": false
     },
     "status": "open",
+    "severity": "low",
     "tags": [],
     "title": "stack",
     "updated_at": "2022-03-29T10:33:09.754Z",
@@ -62,6 +63,7 @@
       "syncAlerts": false
     },
     "status": "open",
+    "severity": "low",
     "tags": [],
     "title": "stack",
     "updated_at": "2022-03-29T10:33:09.754Z",
@@ -104,6 +106,7 @@
       "syncAlerts": false
     },
     "status": "open",
+    "severity": "low",
     "tags": [],
     "title": "stack",
     "updated_at": "2022-03-29T10:33:09.754Z",