`quoteAddressToFormAddressData` mutates the argument

[vaaralav]

Preconditions

1. Magento >=2.1.9 (at least)

Steps to reproduce

1. Require 'Magento_Checkout/js/model/address-converter' inside any JavaScript module.
2. Call quoteAddressToFormAddressData method with some address.

Expected result

1. address.street should remain as an array. Eg. ['Sesame Street']

Actual result

1. address.street becomes an object. Eg. {0: 'Sesame Street'}

[magento-engcom-team]

@vaaralav, thank you for your report.
We've acknowledged the issue and added to our backlog.

[magento-engcom-team]

Hi @vaaralav. Thank you for your report.
The issue has been fixed in #14250 by @mastiuhin-olexandr in 2.3-develop branch
Related commit(s):

• c71e7acb4e13e3b2848a77353345de1b03fe0d5e

The fix will be available with the upcoming 2.3.0 release.