[Bug] When migrating an elastic agent from one fleet server to another the Endpoint Security still sent logs to the old one

While testing elastic Agent I had a host connected to one Fleet server in a policy that had Endpoint Security as an integration. I then used the `elastic-agent enroll` command to enroll the agent with a different Fleet server, this time with a policy that only included the OSQuery integration. After migrating to the new Fleet server the Elastic Agent reported that only the OSQuery integration was installed, but Endpoint Security was still installed and sending events to the old Fleet server.

Elastic Agent 7.15.1
MacOS VM running Mac OS 12.0.1. The VM was running OS 10.15.1 when the original agent was installed but it was upgraded to OS 12.0.1 after migrating it to the new fleet server.

Slack Conversation about this: https://elastic.slack.com/archives/C01QQ449KE1/p1635253469053200