refactor(payment_methods): store `card_network` in locker

[Chethan-rao]

Type of Change

• [ ] Bugfix
• [ ] New feature
• [ ] Enhancement
• [x] Refactoring
• [ ] Dependency updates
• [ ] Documentation
• [ ] CI/CD

Description

We have card_brand field in locker which is None currently for all cards. When a card_network is sent in the request, we map it to card_brand and store it in locker.

Additional Changes

• [ ] This PR modifies the API contract
• [ ] This PR modifies the database schema
• [ ] This PR modifies application configuration/environment variables

Motivation and Context

How did you test it?

1. Store a payment method in locker with card_network field in request.

curl --location 'http://localhost:8080/payment_methods' \
--header 'Content-Type: application/json' \
--header 'Accept: application/json' \
--header 'api-key: abc' \
--data '{
    "payment_method": "card",
    "payment_method_type": "credit",
    "payment_method_issuer": "Visa",
    "card": {
        "card_number": "4111111111111111",
        "card_exp_month": "04",
        "card_exp_year": "25",
        "card_holder_name": "John",
        "card_network": "Visa"
    },
    "customer_id": "cus_spLo0JPwK16PTtBuIk1b",
    "metadata": {
        "city": "NY",
        "unit": "245"
    }
}'

2. Retrieve stored card with list_customer_payment_methods and verify whether card_network is populated.

Checklist

• [x] I formatted the code cargo +nightly fmt --all
• [x] I addressed lints thrown by cargo clippy
• [x] I reviewed the submitted code
• [ ] I added unit tests for my changes where possible
• [ ] I added a CHANGELOG entry if applicable