Here’s some perspective from a man one day removed from the birth of his first child. “It was the happiest day of my life,” Dallas Mavericks guard Luka Doncic said with a smile on Saturday night. He of course was referring to Friday, the day his daughter, Gabriela, was born. “But today’s game was a big roller coaster, too.” A roller coaster equal to the welcoming of a new child? Well, no, of…