Sorbet / Tapioca DSL support

[SamMorrowDrums]

I've opened https://github.com/Shopify/tapioca/issues/2235 but the core issue is that we lose the type information from the GRPC DSL that tapioca provides when the twirp layer is added, so unfortunately calls to twirp-ruby in ruby apps with Sorbet do not get the benefit of type information, as the twirp layer adds a lay of indirection which leads to the interfaces all being untyped.

It would be amazing if it were possible to provide this somehow.