fix(router): make payment type optional in payments request (#2465)

Author: vspecky

crates/api_models/src/payments.rs

@@ -301,8 +301,7 @@ pub struct PaymentsRequest {
 
     /// The type of the payment that differentiates between normal and various types of mandate payments
     #[schema(value_type = Option<PaymentType>)]
-    #[serde(default)]
-    pub payment_type: api_enums::PaymentType,
+    pub payment_type: Option<api_enums::PaymentType>,
 }
 
 #[derive(Default, Debug, Clone, Copy)]

crates/router/src/routes/payments.rs

@@ -871,7 +871,7 @@ where
     // the operation are flow agnostic, and the flow is only required in the post_update_tracker
     // Thus the flow can be generated just before calling the connector instead of explicitly passing it here.
 
-    match req.payment_type {
+    match req.payment_type.unwrap_or_default() {
         api_models::enums::PaymentType::Normal
         | api_models::enums::PaymentType::RecurringMandate
         | api_models::enums::PaymentType::NewMandate => payments::payments_core::<