SACRAMENTO — The Lakers took another step tonight with their victory over the Sacramento Kings at Arco Arena. They broke open the game with a 9-0 run that bridged the end of the third quarter and the start of the fourth. Kobe Bryant scored 30 points and added nine rebounds and seven assist as the Lakers won their 50th game of the season. Pau Gasol had 28 points and 12 rebounds and Andrew Bynum had 21 points and 12 rebounds. The Lakers haven’t had three players with 20 or more points plus 10 or more rebounds in the same game since Kareem Abdul-Jabbar, Magic Johnson and James Worthy did it in a game Dec. 21, 1984 against the Phoenix Suns.