By Martin Baccardax Tesla’s March China sales were up 85% from last year, but overall sales in the world’s biggest car market slumped lower amid Covid-linked plant closures and consumer restrictions. Tesla (TSLA) – Get Tesla Inc Report shares slumped lower Monday after data showed car sales in China fell for the first time in three months as the country’s ‘zero Covid’ policy shutters factories and limited consumer and business activity in the world’s largest auto market. The China Association of Automobile Manufacturers said March sales fell 11.7% from last year to 2.23 million units, a notabl…