this is a typo -

status

should be changed to

statuses

query FilteredPipelineRuns {
  pipelineRunsOrError(filter: { statuses: [FAILURE] }) {
    __typename
    ... on PipelineRuns {
      results {
        runId
        pipelineName
        status
        runConfigYaml
        stats {
          ... on PipelineRunStatsSnapshot {
            startTime
            endTime
            stepsFailed
          }
        }
      }
    }
  }
}