/telegrafs POST with config property not in TOML format can lead to HTTP 500

Steps to reproduce:
List the minimal actions needed to reproduce the behavior.

1. create a telegraf request body that contains only the properties name, description, orgID and config (Note that according to the OpenApi definitions this is a valid combination)
2. POST the request to the /telegrafs endpoint

Expected behavior:
Either this is an invalid combination with missing required fields or illegal fields, in which case an HTTP 400 would be returned with a relevant error message, or this is a valid combination, in which case an HTTP 201 would be returned with a copy of the new object.

Actual behavior:
Returns HTTP 500 internal server error.

Environment info:
Testing against K8S-IDPE remocal.

commit d9ae58d52e827a111fe8dedbc125077742f1c61a (HEAD -> master, origin/master, origin/HEAD)
Author: Madu Mitha Ravi <63928819+MaduMitha-Ravi@users.noreply.github.com>
Date:   Thu Nov 10 22:09:40 2022 -0500

Related Issue
https://github.com/influxdata/openapi/issues/611

Start by reproducing the reported POST to the /telegrafs endpoint with only name, description, orgID, and config, then compare the behavior with the OpenAPI definitions and related issue 611. Done means the request is rejected with a relevant HTTP 400 when invalid, or succeeds with HTTP 201 and the new object when valid, rather than returning HTTP 500.