We once owned two cats. When we had guests, they were confined to the laundry with litter tray, blankets, toys, food & water. Some of my guests never even knew we had cats.
Having said....I agree with most of what was mentioned here....honesty is the best policy.
You could frame your request...."Thank you for inviting us and of course, we'd love to come, but during our last visit, one of your dogs got feisty and bit DH. We don't want a repeat performance so would you be able to keep them confined for the evening?
(if reply is no) "......I understand. No need to secure the pooches on our behalf and no hard feelings....Going forward, we'll just have to figure out a way for us to get together elsewhere. "