Get Role Mappings optional roles field (#2474) (#2475)

The roles is optional the same way as role_templates is.
ES in both 7.17 https://github.com/elastic/elasticsearch/blob/92f290e9537478f85ff3fe3ab39945c1a49a[…]k/core/security/authc/support/mapper/ExpressionRoleMapping.java and master (8.13) https://github.com/elastic/elasticsearch/blob/09df99393193b2c53d92899662a8b8b3c55b[…]k/core/security/authc/support/mapper/ExpressionRoleMapping.java
would only show the roles and roles_templates fields in the response if they are non-empty.

(cherry picked from commit 591a05e)
Authored-by: Albert Zaharovits <[email protected]>

Author: github-actions[bot]

specification/security/_types/RoleMapping.ts

@@ -25,7 +25,9 @@ import { RoleTemplate } from './RoleTemplate'
 export class RoleMapping {
   enabled: boolean
   metadata: Metadata
-  roles: string[]
-  rules: RoleMappingRule
+  // Exactly one of roles or role_templates should be set
+  roles?: string[]
+  // Exactly one of roles or role_templates should be set
   role_templates?: RoleTemplate[]
+  rules: RoleMappingRule
 }

specification/security/put_role_mapping/SecurityPutRoleMappingRequest.ts

@@ -37,7 +37,9 @@ export interface Request extends RequestBase {
   body: {
     enabled?: boolean
     metadata?: Metadata
+    // Exactly one of roles or role_templates must be specified
     roles?: string[]
+    // Exactly one of roles or role_templates must be specified
     role_templates?: RoleTemplate[]
     rules?: RoleMappingRule
     run_as?: string[]