Fix remove file on initial comment (go-gitea#20127)

Store the file uuid(which is returned by Gitea in the upload file
response) onto the file object, so it can be used for the remove feature
to specify this file.

Fix go-gitea#20115

Author: Gusted

web_src/js/features/common-global.js

@@ -192,7 +192,8 @@ export function initGlobalDropzone() {
       thumbnailWidth: 480,
       thumbnailHeight: 480,
       init() {
-        this.on('success', (_file, data) => {
+        this.on('success', (file, data) => {
+          file.uuid = data.uuid;
           const input = $(`<input id="${data.uuid}" name="files" type="hidden">`).val(data.uuid);
           $dropzone.find('.files').append(input);
         });

web_src/js/features/repo-legacy.js

@@ -300,6 +300,7 @@ async function onEditContent(event) {
         thumbnailHeight: 480,
         init() {
           this.on('success', (file, data) => {
+            file.uuid = data.uuid;
             fileUuidDict[file.uuid] = {submitted: false};
             const input = $(`<input id="${data.uuid}" name="files" type="hidden">`).val(data.uuid);
             $dropzone.find('.files').append(input);