make dir prop optional in Download Attachment

Since file content is returned from the `run` method of the action, the
action can be used in Connect without persisting the file for later use.

Author: js07

components/zoho_crm/actions/download-attachment/download-attachment.mjs

@@ -42,6 +42,7 @@ export default {
       type: "dir",
       accessMode: "write",
       sync: true,
+      optional: true,
     },
   },
   async run({ $ }) {