fix(diet): remove duplicate BigDecimal import

cfc-backend/src/main/java/com/etotem/cfc/service/BeijingNutritionService.java

@@ -23,7 +23,6 @@ import org.springframework.transaction.annotation.Transactional;
 import javax.annotation.Resource;
 import java.math.BigDecimal;
 import java.util.*;
-import java.math.BigDecimal;
 import java.util.stream.Collectors;
 import com.etotem.cfc.util.SortUtil;