Json iterating per child element, rather than by parent element
**Which version of the plugin are you using?**
[ ] Data Populator for Sketch
[x ] Data Populator for Adobe XD

**Describe the bug**
Plugin is iterating through json keys for every layer, ignoring the intended grouping structure within XD. For example, in the "Contact" example you provided, rather than filling the first group with values from the first item in the data, it instead uses the first item for the name element, then the second item for the image element, ([0].image, [0].firstname, [0].job, [0].email, etc, it instead fills it in with [0].image, [1].firstname, [2].job, [3].email), etc. 

Specifically: the first card has the image for Cheryl Carter, which is from the data item with `id:1`. But for the 'Primary Info' layer, it lists 'Heather Morales's name instead, which is from the `id:2`'s data. Additionally, the 'Secondary Info' uses job / company values from `id:3`'s data, and the two 'Additional Info' layers are pulling the email from `id:4`'s data, and the phone from `id:5`'s data. 

Interestingly, it's also skipping over every 6th item in the json (in the Contacts example). Presumably because the plugin is treating the BG item as a populatable layer?

The data is technically pulling valid information into the appropriate areas, and is still arguably better than standard lorem ipsum, but it still creates some weird visual confusion. In the provided Lego Minis example, the image of the figure is completely unrelated to the figure's name. It can create visual confusion for the person looking it over, and distract them from the design itself, instead inviting discussion on the wrong topic (why the data is 'wrong'). 

**To Reproduce**
Just run the plugin in your Contacts example as described above. Probably easier to see when you turn off randomization.

**Expected behavior**
I would expect the plugin to respect the grouping of the items in XD. When using a repeating grid, first item in the grid should use data from item 1 in the json, and the second item in the grid should use the data from item 2 in the json, etc. 

**Screenshots**
Contacts screenshot that shows the data for each card using data from multiple items in the feed, and failing to populate the entire grid because it ran out of data as a result:
![datapopulator-issu](https://user-images.githubusercontent.com/1060680/115620578-f1d7ca80-a2ba-11eb-88a4-e7ba7eac5c8b.png)

**Environment (please complete the following information):**
 - Windows 10 Pro x64
 - Adobe XD 38.1.12.2
 - Plugin Version 4.0.0