Single word names are duplicated during PayPal transactions

[RyanofWoods]

Current behavior
Single names entered in the Solidus shipping address form become duplicated with a space between during PayPal transactions. (I have not checked Venmo or CreditCard). This seems due to paypal_button.js logic when sending a request to TransactionsController.

Expected behavior
A single name should not be modified by the time of completion.

To Reproduce
Ensure you have PayPal enabled.

1. On the shipping stage, add only one word to the name field, such as John to the billing address.
2. Use the billing address for the shipping address.
3. Continue to checkout using PayPal.

The name will have become John John.

Solidus Version:
Using main at v4.1.0.dev / 474877aaad9139a0a9b8564a9e7279e5446bc12c (bin/sandbox).

Additional context
The shipping address is entered in Solidus, sent to PayPal, then sent back to Solidus (this logic has been quite problematic).

Solidus changed from using firstname and lastname to name, to be more inclusive of countries where only one name is used. This bug defeats the purpose of that.

[tvdeyen]

Now that we merged https://github.com/solidusio/solidus_braintree/pull/160/files into main, do you mind to test again?