fix(specs): make enabled nullable (#1212)

Author: kai687

specs/search/paths/rules/searchRules.yml

@@ -30,6 +30,7 @@ post:
               $ref: '../../../common/parameters.yml#/hitsPerPage'
             enabled:
               type: boolean
+              nullable: true
               default: null
               description: When specified, restricts matches to rules with a specific enabled status. When absent (default), all rules are retrieved, regardless of their enabled status.
             requestOptions: