Fixed attachment field type (#4811)

updatedAt and deletedAt field changed to string like createdAt field. On
file upload updatedAt field will be given date same as createdAt.

Co-authored-by: Lucas Bordeau <bordeau.lucas@gmail.com>

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

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