EMMA BATHA MORE than 700 figures from Britain's music world, including pop star Rita Ora, One Direction singer Niall Horan and producer Nile Rodgers, united to "wipe out racism" declaring "silence is not an option" in response to discrimination and abuse. The pledge made in a letter published in Britain's Sunday Times newspaper comes four decades after British musicians banded together for Rock Against Racism - a cultural movement that emerged in 1976 in response to rising xenophobia. The letter comes amid a growing global movement to tackle racism following the death of George Floyd, a Black man, in police…