Add UI regression tests

[erinknight242]

The following issues were fixed by #19, we need to add e2e test cases to cover them.

Editing nested object names

Example contract:

{
  "Contract": {
    "type": "object",
    "properties": {
      "Id": {
        "$ref": "#/Guid",
        "example": "01234567-abcd-0123-abcd-0123456789ab"
      },
      "Timestamp": {
        "type": "string",
        "format": "date-time",
        "example": "2019-01-01T18:14:29Z"
      },
      "OuterParent": {
        "type": "object",
        "properties": {
          "InnerParent": {
            "type": "object",
            "properties": {
              "Child": {
                "type": "object",
                "properties": {
                  "abcd": {
                    "$ref": "#/Guid",
                    "example": "01234567-abcd-0123-abcd-0123456789ae"
                  }
                }
              }
            }
          }
        }
      }
    }
  },
  "Guid": {
    "type": "string",
    "pattern": "^(([0-9a-f]){8}-([0-9a-f]){4}-([0-9a-f]){4}-([0-9a-f]){4}-([0-9a-f]){12})$",
    "minLength": 36,
    "maxLength": 36,
    "example": "01234567-abcd-0123-abcd-0123456789ab"
  }
}

1. Create a contract as above with a 3x nested field
2. From the root grid, edit OuterParent
3. From the modal window, edit InnerParent
4. Update Inner Parent's name and save
5. OuterParent modal rows should show with updated name
6. Save Outer Parent; root grid should show edited InnerParent name
7. Edit InnerParent from the root grid
8. From the modal window, edit Child
9. Update Child's name and save
10. InnerParent modal rows should show with updated name
11. Save InnerParent; root grid should show updated child name
12. Edit Outer Parent from the root grid
13. From the modal window, edit Child (skipping a level down)
14. Update Child's name and save
15. OuterParent modal rows should show with Child name updated

(This feels like it should be 3 separate cases, except the previous issue was only happening when they were strung together, so best to make it one case)

Adding nested objects

1. Using the same starting object described above, edit OuterParent
2. From the modal window, edit Child (skipping a level)
3. Add a new field (primitive type)
4. Add a new field (Define a new model)
5. Save Child
6. OuterParent should show with the new objects added at the correct level in the tree; save the modal
7. Root object should show new rows at the correct spot in the tree