For nearly 50 years, the ramshackle White Stadium in Frederick Law Olmsted’s Franklin Park in Boston has been a monument to neglect. The peeling paint and potholed track a testament to a neighborhood long victimized by the city’s politics of race. Now, this stadium may finally be getting a second life as the home of one of the National Women’s Soccer League’s newest franchises. But in sports-crazed Boston, not everyone is happy. The proposal to renovate White Stadium is now at the heart of a legal challenge playing out in Suffolk County Superior Court. It is also the focus of a political dispute among the families atop Boston’s glittering sports franchises. The stadium battle has landed in the city’s mayoral race, in the form of a candidate, Josh Kraft, the son of Robert, the owner of the New England Patriots. Josh Kraft is against the proposal for the city to split the $191 million renovation cost with the owners of the new women’s soccer team, a group called Boston Unity Soccer Partners.