How do I disable the Windows Firewall service?

Don't. Disabling the Windows Firewall service isn't supported by Microsoft. Disabling it will not only stop the firewall, it will also break IPsec, connection security rules, and many other network-based security features.

Instead of doing anything to the firewall service (mpssvc), you can use netsh to turn off the firewall for all profiles without stopping the actual service:

netsh advfirewall set allprofiles state off

To turn it back on, use

netsh advfirewall set allprofiles state on