Group::getMembers() returns empty for syncronized roles

Problem/Motivation

Webform Group module calls $group->getMembers(['member']);, where the role 'member' is an INSIDER_ID scoped role synced to the global role of AUTHENTICATED_ID. I assume this is similar to the previous default all members default role in Group v1. Webform group supports tokens where it loads all members of a group and emails them. However, calls to ::getMembers() returns empty list, because there doesn't seem to be any accounting for this type of user loading by role ID in group v3 for synchronized roles.

Steps to reproduce

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes