Stake them out over the local anthills and let the evil little bastards eat out their eyes before feasting on their chocolaty flesh.
From the OP:
Unless they make a dishwasher that will let you boil water on top of the stove and then dump it in. 
Don’t dishwashers have heating elements? I thought that’s what the metal loop at the bottom was. Or is that just used for drying, and not washing?
Rent a dog that isn’t allergic to chocolate.
On the slim chance that someone would actually consider this advice/joke; chocolate in large enough quantities will be toxic to most dogs.
Yes, it’s just for drying. Dishwashers and clothes washers don’t heat water themselves.
Travel back in time and tread on the specific butterfly whose death will give rise to the chain of events that will render Theobroma cacao extinct before humans arrive on the scene. Then return to the future and there will be no chocolate on your bowls.
Not true.
Many dishwashers (AmRoyal.com is for sale | HugeDomains for example) have a temperature boost option
Put them in the microwave if they’re not metal. Melts chocolate and sugar, then wipe the bowls clean.
Mine heats up the water – I didn’t realize that not all dishwashers do this.
If your’s doesn’t, then why not let the dishes wait, and focus on repairing the hot water heater?
Even dishwashers with a heat boost option don’t have enough oomph to take cold tap water and get it hot enough for serious dish washing. All they do is turn on the heating element while the dishwasher is running - they don’t have a thermostat or anything to make sure the water reaches some target temperature.