You will need to install a user script manager extension to install this script.
Recently, LinkedIn has started adding people based on your email contacts to their “People You May Know” page. Just to be clear, this is people who do not have a LinkedIn account already, so attempting to add them will have LinkedIn send them a mail on your behalf.
You might note that they cleverly have made them look almost identical to how people who actually have accounts on LinkedIn, so it’s very easy to inadvertently send an invite to someone while using this page.
This script removes these, leaving only actual accounts to be shown on the page.