Specify postMessage target for usercontent iframe

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

src/utils/FileDownloader.ts

@@ -98,7 +98,7 @@ export class FileDownloader {
                 download: name,
                 auto: autoDownload,
             },
-            "*",
+            window.location.origin,
         );
     }
 }