That alert you are referencing is indeed from the Doorbell Camera. The ADC VDB770 has internal temperature sensing which helps it regulate its internal temperature. If its internal temperature gets too high to operate fully, it enters Cool-Down mode.
This alert has no impact on the alarm system, and there is nothing to do, it is just a notification.
From Alarm.com: The device is rated to operate in temperatures between -22°F (-30°C) and 104°F (40°C) and has been tested at even higher ambient air temperatures. If the region where the device is installed is expected to have temperatures near or above 104°F, then it is important that the device not be installed in a location where it will also be subjected to long periods of direct sunlight.