[DO NOT MERGE] Merge Shopper Insights module into Main

[scannillo]

Summary of changes

See equivalent Android PR https://github.com/braintree/braintree_android/pull/943

⚠️ Note: this PR should be merged with a merge commit and not a squash to preserve commit history.

It looks like both this PR and Android had a few PRs merged without squash & merge so the history isn't super tidy, but good to note for the future.

Checklist

• [X] Added a changelog entry

Authors

@scannillo @agedd @KunJeongPark

[scannillo]

Closing due to pushed back timeline for releasing ShopperInsights feature on BT Mobile SDKs.