[Feature Request] `combinedToUniWith` for something that returns an `Uni`

[MartinX3]

Discussed in https://github.com/smallrye/smallrye-mutiny/discussions/918

Uni.combine().all().unis(UniA,UniB).combinedWith { a,b ->
 persist(new C(a,b))
}

returns a Uni<Uni<C>> forcing me to use a .flatMap { it }