How to disable sending BGP communities at group and neighbor level

[dplore]

          Sorry to comment after this was merged, but I am realizing that the NONE option was deprecated by this change. I don't believe that was a good decision.

BGP configuration is based on a model of inheritance where neighbor settings override group settings, which in turn override global settings. Suppose the group or global configuration specifies that standard, extended and large communities should all be transmittable. The configuration of a specific neighbor should be able to override this and make no communities transmittable to that peer. But without a 'NONE' option, how do you do this? A send-community-type leaf-list with no elements is equivalent to no configuration of send-community-type at all, which should mean that the configuration is inherited from a higher context -- but clearly that's not what we want.

TLDR - it should not be assumed that an empty leaf-list is equivalent to 'NONE'.

Originally posted by @nokia1adam in https://github.com/openconfig/public/issues/852#issuecomment-1684261880