fix(core): connector customer id population dependency removed from config

[swetasharma03]

Type of Change

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

Description

• We were required to populate connector_customer_id after merchant migrates the data (data having connector_customer_id) in shopper_reference_id (customer_id for Adyen).

• But connector_customer_id gets populated in router_data only for connectors listed under:

[connector_customer]
connector_list = "adyen,facilitapay,gocardless,hyperswitch_vault,stax,stripe"

To ensure the value gets populated for Adyen (to populate in shopper_reference), we added Adyen to this list.

• 3. But this list also controls whether the CreateConnectorCustomer flow is automatically triggered for the mentioned connectors. As a result, for every Adyen payment, the system attempts to trigger CreateConnectorCustomer, which is not implemented for Adyen.

This caused the error to be repeatedly logged from crates/router/src/core/payments/customers.rs line 69, but payments are still successful.

let connector_customer_id = match resp.response {
        Ok(response) => match response {
            types::PaymentsResponseData::ConnectorCustomerResponse {
                connector_customer_id,
            } => Some(connector_customer_id),
            _ => None,
        },
        Err(err) => {
            logger::error!(create_connector_customer_error=?err);
            None
        }
    };

In this PR, the dependency of connector_customer_id on connector_customer config for getting populated in RouterData is been removed and also Adyen is removed from connector_customer config, which will prevent createConnectorCustomer flow getting triggered for Adyen, but still we can use connector_customer_id (if present after data migration).

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?

2/31 failed

In main, 4/31 failed:

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

[semanticdiff-com]

Review changes with  

Changed Files

File	Status
crates/router/src/core/payments/customers.rs	53% smaller
config/config.example.toml	Unsupported file format
config/deployments/integration_test.toml	Unsupported file format
config/deployments/production.toml	Unsupported file format
config/deployments/sandbox.toml	Unsupported file format
config/development.toml	Unsupported file format
config/docker_compose.toml	Unsupported file format
loadtest/config/development.toml	Unsupported file format