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 cylc/cylc-uiserver#290 deals with this, but will need to revisit it)

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

cylc-ui/src/utils/aotf.js

Lines 954 to 962 in 3d64d28

	const { result } = response.data[mutation.name]
	if (Array.isArray(result) && result.length === 2) {
	// regular [commandSucceeded, message] format
	if (result[0] === true) {
	// success
	return _mutateSuccess(result[1])
	}
	// failure (Cylc error, e.g. could not find workflow <x>)
	return _mutateError(mutation.name, result[1], response)