By Nadine Schimroszik and Christoph Steitz POTSDAM, Germany (Reuters) -Tesla Inc received a conditional go-ahead for its German gigafactory near Berlin on Friday, the state of Brandenburg said, ending months of delay for the 5 billion euro ($5.5 billion) landmark plant. The gigafactory, which is crucial to Tesla Chief Executive Elon Musk’s ambitions to vanquish European market leader Volkswagen, was initially supposed to open last summer. Germany’s largest automaker has the upper hand in Europe, with a 25% share of electric vehicle (EV) sales to Tesla’s 13%. Brandenburg state premier Dietmar W…