Is the circulating report true that Omar ibn Al-Khattab, may Allah be pleased with him, supplicated with "O Allah, make me among Your few servants" after a man cited the Almighty's saying: "And few of My servants are grateful"?

The narration mentioned in the question has not been judged as authentic or weak. As for the argument "most people do it" to commit a sin, it is refuted by Allah's saying: "And if you obey most of those on the earth, they will mislead you far from Allah's Way" and "And most of mankind will not believe, however much you desire it." And as Al-Fudayl ibn Iyad said: "Follow the path of guidance, and do not be bothered by the scarcity of those who follow it. And beware of the paths of misguidance, and do not be deceived by the multitude of those who perish."