Running mutation on 2 workflows displays error

[MetRonnie]

In a mutation form, adding multiple workflows to run the mutation on results in an error snackbar.

This is because the response we get from the UIServer is in an odd format:

{
  "data": {
    "trigger": {
      "result": [
        {
          "trigger": {
            "result": [
              {
                "id": "~user/thing/run1",
                "response": [
                  true,
                  "d78b43de-7172-4135-afe6-346edbb02cec"
                ]
              }
            ],
            "__typename": "Trigger"
          }
        },
        {
          "trigger": {
            "result": [
              {
                "id": "~user/thing/run2",
                "response": [
                  true,
                  "dba6b04d-a618-4b40-89ca-21f96721f214"
                ]
              }
            ],
            "__typename": "Trigger"
          }
        }
      ],
      "__typename": "Trigger"
    }
  }
}

(I think https://github.com/cylc/cylc-uiserver/pull/290 deals with this, but will need to revisit it)

And this is not what the API-on-the-fly code expects

https://github.com/cylc/cylc-ui/blob/3d64d289457d0403258a9e0ae1dd84ffdf513b5b/src/utils/aotf.js#L954-L962