Is "He who is angered and does not get angry is a donkey" a Prophetic hadith?

The statement "Whoever is angered and does not get angry is a donkey" is attributed to Imam Al-Shafi'i, but there is no hadith with this meaning. Islam prohibits anger and encourages patience. The Prophet, peace and blessings be upon him, advised a man, saying: "Do not get angry," because anger leads to estrangement and hinders kindness, and may harm the person who is the object of anger.