Add check to only report progress if content length is known (Adyen#20)

Author: mcguire-james

AdyenNetworking/APIClient/APIClient.swift

@@ -351,8 +351,10 @@ extension APIClient: AsyncAPIClientProtocol {
 
         for try await byte in asyncBytes {
             data.append(byte)
-            let progress = Double(data.count) / Double(contentLength)
-            request.onProgressUpdate?(progress)
+            if contentLength > 0 {
+                let progress = Double(data.count) / Double(contentLength)
+                request.onProgressUpdate?(progress)
+            }
         }
 
         let destinationUrl = try generateFileDestination(