WASHINGTON — President Donald Trump and his top environmental policy officer finalized a move Thursday to undo an Environmental Protection Agency regulation that laid the foundation for federal rules governing emissions of the greenhouse gases that cause climate change. At a White House event, Trump and EPA Administrator Lee Zeldin said they were officially rolling back the “endangerment finding” that labeled greenhouse gases a threat to public health and provided a framework for the EPA to regulate emissions. The 2009 finding, established under President Barack Obama, called climate change a danger to human health and therefore gave the EPA power to regulate greenhouse gases, such as carbon dioxide from cars and trucks.