Fixed: On Import notifications for webhooks

Closes #4913

src/NzbDrone.Core/Notifications/Webhook/Webhook.cs

@@ -50,8 +50,8 @@ namespace NzbDrone.Core.Notifications.Webhook
                 Episodes = episodeFile.Episodes.Value.ConvertAll(x => new WebhookEpisode(x)),
                 EpisodeFile = new WebhookEpisodeFile(episodeFile),
                 IsUpgrade = message.OldFiles.Any(),
-                DownloadClient = message.DownloadClientInfo.Name,
+                DownloadClient = message.DownloadClientInfo?.Name,
-                DownloadClientType = message.DownloadClientInfo.Type,
+                DownloadClientType = message.DownloadClientInfo?.Type,
                 DownloadId = message.DownloadId
             };