By ALEX VEIGA, AP Business Writer LOS ANGELES (AP) — Soaring home prices have pushed up average homeowner equity growth to the highest level in more than a decade, though recent signs of a cooling U.S. housing market point to more moderate gains in the second half of the year. Homes with a mortgage gained an average of $51,500 in equity in the second quarter, an increase of 29.3% from the April-June