Fix: Handle undefined fileName during attachment download

- Addressed issue where attachments, especially those added via drag and drop, lacked the `fileName` attribute, causing download failures.
- Enhanced the fallback mechanism to generate file name from URL when `fileName` is missing.
- Updated the fileName logic in `fileDownload` across iOS, Android, and web implementations.

src/libs/fileDownload/index.android.js

@@ -32,7 +32,7 @@ function hasAndroidPermission() {
 /**
  * Handling the download
  * @param {String} url
- * @param {String} fileName
+ * @param {String} [fileName]
  * @returns {Promise<Void>}
  */
 function handleDownload(url, fileName) {
@@ -41,7 +41,7 @@ function handleDownload(url, fileName) {
 
         // Android files will download to Download directory
         const path = dirs.DownloadDir;
-        const attachmentName = FileUtils.appendTimeToFileName(fileName) || FileUtils.getAttachmentName(url);
+        const attachmentName = fileName ? FileUtils.appendTimeToFileName(fileName) : FileUtils.getAttachmentName(url);
 
         const isLocalFile = url.startsWith('file://');
 
@@ -96,7 +96,7 @@ function handleDownload(url, fileName) {
 /**
  * Checks permission and downloads the file for Android
  * @param {String} url
- * @param {String} fileName
+ * @param {String} [fileName]
  * @returns {Promise<Void>}
  */
 export default function fileDownload(url, fileName) {

src/libs/fileDownload/index.ios.js

@@ -68,14 +68,14 @@ function downloadVideo(fileUrl, fileName) {
 /**
  * Download the file based on type(image, video, other file types)for iOS
  * @param {String} fileUrl
- * @param {String} fileName
+ * @param {String} [fileName]
  * @returns {Promise<Void>}
  */
 export default function fileDownload(fileUrl, fileName) {
     return new Promise((resolve) => {
         let fileDownloadPromise = null;
         const fileType = FileUtils.getFileType(fileUrl);
-        const attachmentName = FileUtils.appendTimeToFileName(fileName) || FileUtils.getAttachmentName(fileUrl);
+        const attachmentName = fileName ? FileUtils.appendTimeToFileName(fileName) : FileUtils.getAttachmentName(fileUrl);
 
         switch (fileType) {
             case CONST.ATTACHMENT_FILE_TYPE.IMAGE:

src/libs/fileDownload/index.js

@@ -6,7 +6,7 @@ import tryResolveUrlFromApiRoot from '../tryResolveUrlFromApiRoot';
 /**
  * Downloading attachment in web, desktop
  * @param {String} url
- * @param {String} fileName
+ * @param {String} [fileName]
  * @returns {Promise}
  */
 export default function fileDownload(url, fileName) {
@@ -32,7 +32,7 @@ export default function fileDownload(url, fileName) {
                 link.style.display = 'none';
                 link.setAttribute(
                     'download',
-                    FileUtils.appendTimeToFileName(fileName) || FileUtils.getAttachmentName(url), // generating the file name
+                    fileName ? FileUtils.appendTimeToFileName(fileName) : FileUtils.getAttachmentName(url), // generating the file name
                 );
 
                 // Append to html link element page