Fix inverted condition with refunds (#3539)

Signed-off-by: Emma Alexia <emma@modrinth.com>

apps/labrinth/src/routes/internal/billing.rs

@@ -206,7 +206,7 @@ pub async fn refund_charge(
             ));
         }
 
-        let (id, net) = if refund_amount != 0 {
+        let (id, net) = if refund_amount == 0 {
             (None, None)
         } else {
             match charge.payment_platform {