By Matt Spetalnick and Vivian Sequera WASHINGTON/CARACAS (Reuters) – The U.S. on Monday began reinstating sanctions on Venezuela and a Biden administration source said a roll-back of restrictions on the oil industry could be allowed to expire, after the South American country’s top court upheld a ban blocking the candidacy of the leading opposition hopeful in presidential elections. The United States had granted sanctions relief for OPEC member Venezuela in October in recognition of a deal for elections this year. But that relief was conditioned on President Nicolas Maduro’s government freeing…