[EDR Workflows] Set Agent Tamper Protection to false on policy unassi…

…gnment (elastic#193017)

This PR fixes an issue where Agent Tamper Protection remained enabled
even after a Defend policy was unassigned from the agent policy.

There is no issue with removing the integration; it still causes agent
tamper protections to be disabled.


https://github.com/user-attachments/assets/ee105e60-3db2-4249-a33b-44a2f2f7aac9