fix(engine): use the bad request status instead of server error (#434)

Description

Use the bad request status instead of server error

Related issue

#434 (closed)

Examples

GET /api/admin/config

Status code: 400

{
  "code": "BAD_REQUEST",
  "message": "config is only available in logical mode"
}

POST /api/admin/test-db-source

Status code: 400

{
  "code": "BAD_REQUEST",
  "message": "the endpoint is only available in the Logical mode of the data retrieval"
}

Checklist

• MR description has been reviewed
• MR changes are functionally tested
• MR does NOT have text changes OR there are text changes and they have been reviewed
• MR does NOT have API/CLI changes OR there are API/CLI changes and they have been reviewed
• MR does NOT have UI changes OR there are UI changes and they have been reviewed

Closes #434 (closed)