itemSelected event does not get triggered on contentEditable if there is a placeholder set

[pavan999-dev]

Setup:

1. Set placeholder in the contentEditable item like ngx-wig
2. Type trigger character like '@' mention list gets opened

Issue is:
When you select item from the mention list itemSelected event does not get triggered.

Below is the demo of the issue
https://stackblitz.com/edit/ngx-wig-sample-plugins-v1aqnkiw?file=package.json,src%2Fapp.ts,angular.json