src: remove KeyObjectData::symmetric_key_len_
symmetric_key_len_ is always equal to symmetric_key_.size(). Storing it separately is redundant and has no significant benefit.
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
symmetric_key_len_ is always equal to symmetric_key_.size(). Storing it separately is redundant and has no significant benefit.