fix(ui): execute client upload handler only when file exists (#11538)

Fixes #11537

Author: r1tsuu

packages/ui/src/elements/BulkUpload/FormsManager/createFormData.ts

@@ -18,11 +18,10 @@ export async function createFormData(
     delete data.file
   }
 
-  let clientUploadContext = null
-
-  if (typeof uploadHandler === 'function') {
+  if (file && typeof uploadHandler === 'function') {
     let filename = file.name
-    clientUploadContext = await uploadHandler({
+
+    const clientUploadContext = await uploadHandler({
       file,
       updateFilename: (value) => {
         filename = value

packages/ui/src/forms/Form/index.tsx

@@ -507,10 +507,9 @@ export const Form: React.FC<FormProps> = (props) => {
 
       const handler = getUploadHandler({ collectionSlug })
 
-      if (typeof handler === 'function') {
-        let clientUploadContext = null
+      if (file && typeof handler === 'function') {
         let filename = file.name
-        clientUploadContext = await handler({
+        const clientUploadContext = await handler({
           file,
           updateFilename: (value) => {
             filename = value