Haven’t come across anyone who has, I think it’s an insurance issue for beauty companies though in regards to treating diabetics, wouldn’t believe the procedure is an issue as it’s a widely used beauty procedure but you would have to declare your T1 status and the clinic has the right to refuse to treat you.
Apart from beauty procedures, botox is also used to treat gastroparesis. Gastroparesis is often caused by diabetes so I'd think there must be quite some T1's who've had this procedure.