How authentic is the attribution to Umar ibn al-Khattab, may Allah be pleased with him, of the saying, "The dog stabbed me," regarding the one who stabbed him during prayer?

The story mentioned in Sahih al-Bukhari about 'Umar, may Allah be pleased with him, being stabbed during the Fajr prayer, where he said, "The dog has killed me," to inform people about what happened to him. He قطع his prayer and did not continue it, but rather took 'Abd al-Rahman ibn 'Awf by the hand to lead the people in a brief prayer. 'Umar then prayed Fajr later in his home, with his wound bleeding. There is no issue with this, as he did not utter the words while in prayer. As for cursing the killer and describing him as a dog, it is permissible because he deserved to be cursed, in accordance with the Almighty's saying: "Allah does not like the public utterance of evil, except by one who has been wronged" [Quran 4:148], and this Caliph was subjected to a great injustice.