Fix #4987: Can't populate tag string from upload url anymore.

Usage: https://danbooru.donmai.us/uploads/new?url=...&post[tag_string]=...&post[rating]=...

* Pass the URL parameters from the /uploads/new page to the /uploads/:id page.
* Fix the /uploads/:id page throwing an "unpermitted parameters" error
  when given URL params for the post edit form.

app/components/file_upload_component/file_upload_component.js

@@ -102,7 +102,14 @@ export default class FileUploadComponent {
     }
 
     if (upload.status === "completed") {
-      window.location.replace(`/uploads/${upload.id}`);
+      let params = new URLSearchParams(window.location.search);
+      params.delete("url");
+      params.delete("ref");
+
+      let url = new URL(`/uploads/${upload.id}`, window.location.origin);
+      url.search = params.toString();
+
+      window.location.replace(url);
     } else {
       this.$dropzone.removeClass("success");
       this.$component.find("progress").addClass("hidden");