Fix Null ref in SendPaginatedMessage

Created by: Kiritsu

Summary

Fixes the Null Reference Exception that occures in GeneratePaginationReactions. The parameter emojis in method SendPaginatedMessage has null value by default. If you were not passing an instance of PaginationEmojis it would throw when trying to call GeneratePaginationReactions

Details

Simply check if emojis is null and instanciate it in case it's null.