feat: collect address on checkout if it is required for taxation, and sync it

[anujk14]

Currently, if stripe_auto_tax is enabled, and the user does not have an address associated with the billing account, we get an error from stripe as follows:

{
    "code": "customer_tax_location_invalid",
    "doc_url": "https://stripe.com/docs/error-codes/customer-tax-location-invalid",
    "status": 400,
    "message": "Automatic tax calculation in Checkout requires a valid address on the Customer. Add a valid address to the Customer or set either `customer_update[address]` to 'auto' or `customer_update[shipping]` to 'auto' to save the address entered in Checkout to the Customer.",
    "request_id": "",
    "request_log_url": "",
    "type": "invalid_request_error"
}

In order to fix this, the customer_update[address] field needs to be set to auto in order to collect the billing address for taxation during the checkout. This address is later synced back to Frontier's database in the syncWithProvider method in checkouts.

Stripe checkout screen when address is not pre-added:

Stripe checkout screen when address was already added earlier to stripe account:

[vercel[bot]]

The latest updates on your projects. Learn more about Vercel for Git ↗︎

Name	Status	Preview	Comments	Updated (UTC)
frontier	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	Apr 2, 2024 9:38am

[coveralls]

Pull Request Test Coverage Report for Build 8520653293

Details

• 0 of 23 (0.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.002%) to 9.778%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
billing/checkout/service.go	0	23	0.0%
<!--	Total:	0	23

Totals
Change from base Build 8518134174:	-0.002%
Covered Lines:	9457
Relevant Lines:	96717

---

💛 - Coveralls