PBXGroups: make sure we're only adding to the top-level group

[rgomezp]

Description

One Line Summary

Fixes #226 by restricting PBXGroups we add NSE files to.

Details

Motivation: other groups may have an undefined "name" property other than the top level

Fix #226

Motivation

In some cases, other PBXGroups can meet the criteria such as "Pods", or "" (un-named) groups. However, we should not add NSE files to these.

Testing

Manual testing

Tested manually by creating a beta release (2.0.3-beta.0) and running an EAS managed build. However, this introduced a new problem described here.

Deleting and recreating 1) Distribution certificates and 2) Provisioning profiles via eas credentials did the trick.

Checklist

Overview

• I have filled out all REQUIRED sections above
• PR does one thing
  • If it is hard to explain how any codes changes are related to each other then it most likely needs to be more than one PR
• Any Public API changes are explained in the PR details and conform to existing APIs

Testing

• I have personally tested this on my device, or explained why that is not possible
• I have tested this on the latest version of the plugin
• I have tested this on both Android and iOS, or explained why that is not possible
  - Only impacts iOS

Final pass

• Code is as readable as possible.
  • Simplify with less code, followed by splitting up code into well named functions and variables, followed by adding comments to the code.
• I have reviewed this PR myself, ensuring it meets each checklist item
  • WIP (Work In Progress) is ok, but explain what is still in progress and what you would like feedback on. Start the PR title with "WIP" to indicate this.