By Abinaya V and Nivedita Balu (Reuters) -Tesla Inc Chief Executive Elon Musk disclosed on Monday he had abandoned a plan to join Twitter Inc’s board just as his tenure was about to start, the latest move by the world’s richest man that defied corporate America’s norms. Musk revealed last week he had accepted a board seat at Twitter, contradicting a regulatory filing he had published a day earlier in which he described himself as a passive investor. Sources told Reuters at the time that Musk asked Twitter for a board seat weeks before the social media company agreed to the arrangement. Musk an…