Interface inheritance is an excellent tool, though you should only use it when interface B is truly substitutable for interface A, not just to aggregate loosely-related behaviors.
It’s difficult to tell whether it is appropriate for your specific case, but there’s nothing wrong using the practice in principle. You see it in the first-rate APIs all the time. To pick just one common example, from the .NET framework:
public interface ICollection<T> : IEnumerable<T>, IEnumerable