Unhelpful error message on missing directive

[roelvandun]

Description

Checking the proposed schema for subgraph xxx against xxx-test-vg2wz@current
error[E005]: The response from Apollo Studio was malformed. Response body contains `null` value for 'graph.checkWorkflow....on OperationsCheckTask.result'
        This error was unexpected! Please submit an issue with any relevant details about what you were trying to do: https://github.com/apollographql/rover/issues/new/choose

Steps to reproduce

I was doing the GraphQL schema check, but it kept failing. Ultimately, I found out that this was caused by the absence of this code:

directive @contact(
  name: String!
  url: String
  description: String
) on SCHEMA

Expected result

It would be helpful if Rover would point out this missing directive instead of giving this cryptic error message.

Actual result

See the description

Environment

Run rover info and paste the results here

If you can't run rover info for some reason, please provide as much of the following info as possible:

• Operating system and version: check initiated by Github Workflow
• Shell (bash/zsh/powershell):
• Version of Rover (rover --help):
• Apollo Studio Plan: [free/team/enterprise/none]
• Installation method: [curl/npm/npx/build from source]