Does the saying, "There is no god but Allah," when pouring tea on occasions, as is customary in Morocco, have a legal basis in Islamic law?

Allocating a specific dhikr at a specific time for which there is no evidence is considered an innovation (bid‘ah). There is no mention in Islamic law of reciting "La ilaha illallah" (There is no god but Allah) when distributing food or drink at weddings or funerals. Therefore, this act is not permissible.