By Anirban Sen and Tom Hals (Reuters) – Billionaire Elon Musk is proposing to go ahead with his original offer of $44 billion to take Twitter Inc private, a securities filing showed on Tuesday, signaling an end to a legal battle that could have forced Musk to pay up. An agreement would put the world’s richest person in charge of one of the most influential media platforms and end months of litigation that damaged Twitter’s brand and fed Musk’s reputation for erratic behavior. Musk, the chief executive of electric car maker Tesla Inc, will take over a company he originally committed to buying i…