Unassigns a role from group members.
Note: This function is only relevant for site admins, and group members with group admin permissions.
The unassignRole() function returns a Promise that resolves to the unassigned role after it has successfully been unassigned. This function only applies to admin roles. Using this function with member roles returns an error.
Group ID.
Member IDs.
Max: 100 member IDs
Role to unassign.