delete empty files on failed downloads

MareSynchronos/WebAPI/ApIController.Functions.Files.cs

@@ -50,6 +50,8 @@ public partial class ApiController
         response.EnsureSuccessStatusCode();
 
         var fileName = Path.GetTempFileName();
+        try
+        {
             var fileStream = File.Create(fileName);
             await using (fileStream.ConfigureAwait(false))
             {
@@ -69,6 +71,12 @@ public partial class ApiController
                 return fileName;
             }
         }
+        catch
+        {
+            File.Delete(fileName);
+            throw;
+        }
+    }
 
     public int GetDownloadId() => _downloadId++;