update returned data on security test 24 of test suite

doc/testing/testplan/api_security_service/README.md

@@ -1101,8 +1101,10 @@ At this documentation you will have all information and related files and exampl
   1. Response to Request of Access Token:
      1. **400 Bad Request** response.
      2. body returned must accomplish **AccessTokenErr** data structure, with:
-        * error unsupported_grant_type
-        * error_description=Invalid value for `grant_type` \\(${grant_type}\\), must be one of \\['client_credentials'\\] - 'grant_type'
+        * title=Bad Request
+        * detail='not_valid' is not one of \\['client_credentials', 'authorization_code'\\] - 'grant_type'
+        * status=400
+
 
 ## Test Case 25: Retrieve access token with invalid scope