[local-sync] Fix a couple bugs that popped up while sending

- Pass in the account when creating an ImapConnection
- Wrap the return value of the SendMessage task in an object

packages/local-sync/src/local-sync-worker/sync-worker.js

@@ -126,6 +126,7 @@ class SyncWorker {
       db: this._db,
       settings: Object.assign({}, settings, credentials),
       logger: this._logger,
+      account: this._account,
     });
 
     conn.on('mail', () => {

packages/local-sync/src/local-sync-worker/syncback_tasks/send-message.imap.js

@@ -48,7 +48,7 @@ class SendMessageIMAP extends SyncbackTask {
       // actually did
       logger.error(err, 'SendMessage: Could not sent message to sent folder')
     }
-    return message.toJSON()
+    return {message: message.toJSON()}
   }
 }