By Manjul Paul and Shrutee Sarkar BENGALURU (Reuters) - The U.S. economy will grow faster than previously thought and reach pre-COVID-19 levels within six months, according to a majority of economists polled by Reuters who however said unemployment would take well over a year to recover. Optimism was largely driven by the House of Representatives passing President Joe Biden's $1.9 trillion relief aid in response to the pandemic, which has killed around 530,000 people in the U.S. and left millions out of work. After shrinking 3.5 percent last year, the world's largest economy was forecast to grow 5.7 percent...