fix(connector): [CRYPTOPAY] Skip metadata serialization if none (jusp…

…ay#4205)

crates/router/src/connector/cryptopay/transformers.rs

@@ -49,6 +49,7 @@ pub struct CryptopayPaymentsRequest {
  pay_currency: String,
  success_redirect_url: Option<String>,
  unsuccess_redirect_url: Option<String>,
+ #[serde(skip_serializing_if = "Option::is_none")]
  metadata: Option<pii::SecretSerdeValue>,
  custom_id: String,
 }