refactor(payment_methods): make the card_holder_name as an empty string if not sent

[Chethan-rao]

Type of Change

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

Description

This PR includes changes for sending the card_holder_name as an empty string if not sent during confirm or not present 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. Create a noon merchant connector account
2. Create a payment without card_holder_name

curl --location 'http://localhost:8080/payments' \
--header 'Content-Type: application/json' \
--header 'Accept: application/json' \
--header 'api-key: dev_ZBWUNGf7TfqeTnt5VsSYyonTiN3Ohdw4JoEba8frZPmKYaHu9tLLBbMPqmhJcIJl' \
--data-raw '{
    "amount": 6540,
    "currency": "USD",
    "confirm": true,
    "capture_method": "manual",
    "capture_on": "2022-09-10T10:11:12Z",
    "amount_to_capture": 6540,
    "customer_id": "StripeCustomer",
    "business_country": "US",
    "business_label": "default",
    "email": "guest@example.com",
    "name": "John Doe",
    "phone": "999999999",
    "phone_country_code": "+1",
    "description": "Its my first payment request",
    "authentication_type": "no_three_ds",
    "return_url": "https://google.com",
    "setup_future_usage": "on_session",
    "payment_method": "card",
    "payment_method_type": "credit",
    "payment_method_data": {
        "card": {
            "card_number": "4242424242424242",
            "card_exp_month": "10",
            "card_exp_year": "25",
            "card_cvc": "123"
        }
    },
    "shipping": {
        "address": {
            "line1": "1467",
            "line2": "Harrison Street",
            "line3": "Harrison Street",
            "city": "San Fransico",
            "state": "California",
            "zip": "94122",
            "country": "US",
            "first_name": "joseph",
            "last_name": "Doe"
        },
        "phone": {
            "number": "8056594430",
            "country_code": "+91"
        }
    },
    "billing": {
        "address": {
            "line1": "1467",
            "line2": "Harrison Street",
            "line3": "Harrison Street",
            "city": "San Fransico",
            "state": "California",
            "zip": "94122",
            "country": "US",
            "first_name": "joseph",
            "last_name": "Doe"
        },
        "phone": {
            "number": "8056594427",
            "country_code": "+91"
        }
    },
    "statement_descriptor_name": "joseph",
    "statement_descriptor_suffix": "JS",
    "metadata": {
        "udf1": "value1",
        "new_customer": "true",
        "login_date": "2019-09-10T10:11:12Z"
    }
}'

Payment went through even though card_holder_name was a required field because we are sending an empty string if not present or sent

Checklist

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