feat(payment_methods): pass required_billing_contact_fields field in /session call based on dynamic fields (#4601)

Co-authored-by: hyperswitch-bot[bot] <148525504+hyperswitch-bot[bot]@users.noreply.github.com>

crates/api_models/src/enums.rs

@@ -396,13 +396,11 @@ pub struct UnresolvedResponseReason {
     Clone,
     Debug,
     Eq,
-    PartialEq,
     serde::Deserialize,
     serde::Serialize,
     strum::Display,
     strum::EnumString,
     ToSchema,
-    Hash,
 )]
 #[serde(rename_all = "snake_case")]
 #[strum(serialize_all = "snake_case")]
@@ -430,6 +428,89 @@ pub enum FieldType {
     DropDown { options: Vec<String> },
 }
 
+impl FieldType {
+    pub fn get_billing_variants() -> Vec<Self> {
+        vec![
+            Self::UserBillingName,
+            Self::UserAddressLine1,
+            Self::UserAddressLine2,
+            Self::UserAddressCity,
+            Self::UserAddressPincode,
+            Self::UserAddressState,
+            Self::UserAddressCountry { options: vec![] },
+        ]
+    }
+}
+
+/// This implementatiobn is to ignore the inner value of UserAddressCountry enum while comparing
+impl PartialEq for FieldType {
+    fn eq(&self, other: &Self) -> bool {
+        match (self, other) {
+            (Self::UserCardNumber, Self::UserCardNumber) => true,
+            (Self::UserCardExpiryMonth, Self::UserCardExpiryMonth) => true,
+            (Self::UserCardExpiryYear, Self::UserCardExpiryYear) => true,
+            (Self::UserCardCvc, Self::UserCardCvc) => true,
+            (Self::UserFullName, Self::UserFullName) => true,
+            (Self::UserEmailAddress, Self::UserEmailAddress) => true,
+            (Self::UserPhoneNumber, Self::UserPhoneNumber) => true,
+            (Self::UserCountryCode, Self::UserCountryCode) => true,
+            (
+                Self::UserCountry {
+                    options: options_self,
+                },
+                Self::UserCountry {
+                    options: options_other,
+                },
+            ) => options_self.eq(options_other),
+            (
+                Self::UserCurrency {
+                    options: options_self,
+                },
+                Self::UserCurrency {
+                    options: options_other,
+                },
+            ) => options_self.eq(options_other),
+            (Self::UserBillingName, Self::UserBillingName) => true,
+            (Self::UserAddressLine1, Self::UserAddressLine1) => true,
+            (Self::UserAddressLine2, Self::UserAddressLine2) => true,
+            (Self::UserAddressCity, Self::UserAddressCity) => true,
+            (Self::UserAddressPincode, Self::UserAddressPincode) => true,
+            (Self::UserAddressState, Self::UserAddressState) => true,
+            (Self::UserAddressCountry { .. }, Self::UserAddressCountry { .. }) => true,
+            (Self::UserBlikCode, Self::UserBlikCode) => true,
+            (Self::UserBank, Self::UserBank) => true,
+            (Self::Text, Self::Text) => true,
+            (
+                Self::DropDown {
+                    options: options_self,
+                },
+                Self::DropDown {
+                    options: options_other,
+                },
+            ) => options_self.eq(options_other),
+            _unused => false,
+        }
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    #[test]
+    fn test_partialeq_for_field_type() {
+        let user_address_country_is_us = FieldType::UserAddressCountry {
+            options: vec!["US".to_string()],
+        };
+
+        let user_address_country_is_all = FieldType::UserAddressCountry {
+            options: vec!["ALL".to_string()],
+        };
+
+        assert!(user_address_country_is_us.eq(&user_address_country_is_all))
+    }
+}
+
 #[derive(
     Debug,
     serde::Deserialize,