Yeah, some of them definitely contain gluten. But I personally use Cascade Complete and Palmolive dishwashing detergent because they are gluten-free. But anyway, the problems with gluten come if you eat such products. It would be nothing serious if you wash your dishes with soap containing gluten. Just do not eat anything exactly after you cleaned it..or use pure water after that. But in general, I have not noticed any problems with cleaning products since my childhood (I've been gluten-free since 10yo), so it is ok for me to hire companies like
https://procleaninglondon.co.uk/areas/haringey to clean my house. Anyway, be careful with products and always read the product composition.