[Design] Step errors are not reported correctly in the PR comment

[v1v]

Description

This is regarding the enhancement of the GH PR comment, for some reason the steps.json does not contain the message for the error that caused the failure.

Use Case

PRs that are from first time contributors cannot run in the CI automatically, for instance elastic/beats#18061

The description is empty since the steps-errors.json contains the below details

{
  displayDescription: null,
  displayName: "Error signal",
  durationInMillis: 12,
  id: "70",
  input: null,
  result: "FAILURE",
  startTime: "2020-04-28T18:01:17.388+0000",
  state: "FINISHED",
  type: "STEP"
}

From the BO entrypoint

The URL_BO_ENTRYPOINT.../log contains the error message:

Question

Should we manipulate the steps-errors.json to look for all the steps with result: "FAILURE", and with displayDescription: null, to gather their LogStorageAction ?