[MM-42421] Prevent guests from seeing users through groups API (#21151)

api4/group_test.go

@@ -1518,7 +1518,7 @@ func TestAddMembersToGroup(t *testing.T) {
 
 	assert.Len(t, groupMembers, 2)
 
-	count, countErr := th.App.GetGroupMemberCount(group.Id)
+	count, countErr := th.App.GetGroupMemberCount(group.Id, nil)
 	assert.Nil(t, countErr)
 
 	assert.Equal(t, count, int64(2))