Windows Defender: Turn off routine remediation (DisableRoutinelyTakingAction)

Here is how to (temporarily) turn off routine remediation in Windows Defender Antivirus (WinDefend). During the transition of antivirus software to Windows Defender Antivirus (WinDefend), I don't want Windows Defender remediation on threats it might find. Later, when I have more information about potential threats, I can always choose to remediate that threat, e.g. quarantaine or remove it.

How-to fix “Get-MpComputerStatus : The extrinsic Method could not be executed.”

In my situation, I had Windows Defender Antivirus disabled per GPO ("Turn off Windows Defender Antivirus" in Computer Configuration/Administrative Templates/Windows Components/Windows Defender Antivirus), and I wanted to enable Windows Defender in a new GPO, on a specific set of computers. This resulted in an error message "Get-MpComputerStatus : The extrinsic Method could not be executed."