Unnecessary css include in HTML source code

Hello,

I found some unnecessary html code in my source code of home page:

<link rel='stylesheet' id='validate-engine-css-css' href='https://blogginger.com/wp-content/plugins/wysija-newsletters/css/validationEngine.jquery.css' type='text/css' media='all' />

You can check it in live website: https://blogginger.com

Please remove these lines, if these are really useless codes.

Thank you!