Even though Mother Theresa was, indubitably, a very questionable figure, it doesn't seem right to use the argument that: because a pendant of her appears on the site that is cause for alarm.
There are also pendants of Christ on the cross. Christ is not a questionable figure Himself. He is God.
What should shock people (namely true Catholics), above all, is this statement by Mother Theresa:
"There is only one God and He is God to all; therefore it is important that everyone is seen as equal before God. I’ve always said we should help a Hindu become a better Hindu, a Muslim become a better Muslim, a Catholic become a better Catholic. We believe our work should be our example to people. We have among us 475 souls - 30 families are Catholics and the rest are all Hindus, Muslims, Sikhs—all different religions. But they all come to our prayers."
If this is not serious cause for scandal, and a reason to have suspicion that she was a proponent of false ecumenism, then I don't know what is.