[frontend] Add 'Unknown' value in Main Observable Type filter values (#10145)

Author: Archidoit

opencti-platform/opencti-front/src/utils/filters/useSearchEntities.tsx

@@ -973,7 +973,7 @@ const useSearchEntities = ({
                   label: t_i18n('Unknown'),
                   value: 'Unknown',
                   type: 'Unknown',
-                })
+                });
               }
               unionSetEntities(
                 filterKey,