Cannot create logstash pipeline due to broken validation

[mshustov]

In #63135 we migrated Logstash REST API to the KP. This migration tightened up validation rules for https://www.elastic.co/guide/en/kibana/7.9/logstash-configuration-management-api-create.html#logstash-configuration-management-api-create-params endpoint making the id & description fields mandatory in the request body.
The endpoint interface must comply with the official docs.

[elasticmachine]

Pinging @elastic/kibana-platform (Team:Platform)