upload: Name the link based on the uploaded filename.

We previously parsed the filename as stored on disk, which is rather
sanitized.  Use as close to the original filename as possible.

web/tests/upload.test.js

@@ -501,6 +501,7 @@ test("uppy_events", ({override_rewire, mock_template}) => {
     let response = {
         body: {
             url: "/user_uploads/4/cb/rue1c-MlMUjDAUdkRrEM4BTJ/copenhagen.png",
+            filename: "copenhagen.png",
         },
     };