LONDON — Zack Polanski’s Green Party will conduct a sweeping review of its policy platform to weed out unpopular proposals thrust into the spotlight as support for the movement grows. The “eco-populist” leader told POLITICO he is looking to revise the party's democratized — but at times chaotic and unwieldy — system which lets members set the policy agenda. The Greens have for years ticked along in the undergrowth of British politics with a focus on environmental issues, but under Polanski's