Return the list of statistics of jouney under the bundle

Example response

{
  "data": [
    {
      "attributes": {
        "journeyStageStatistics": [
          {
            "stepSizes": {
              "wait_step_abc123": 150,
              "activation_def456": 75
            },
            "stepInfluxes": {
              "wait_step_abc123": 25,
              "activation_def456": 12
            }
          }
        ]
      }
    }
  ]
}