Fix: File Upload (#4806)

File upload issue fixed.
There was a type mismatch and isDate was returning false

packages/twenty-front/src/modules/attachments/types/Attachment.ts

@@ -1,6 +1,6 @@
 export type Attachment = {
   id: string;
-  createdAt: Date;
+  createdAt: string;
   updatedAt: Date;
   deletedAt: Date | null;
 };