fix(portal): Optimized the robustness of the code

apollo-portal/src/main/java/com/ctrip/framework/apollo/openapi/service/ConsumerService.java

@@ -262,7 +262,7 @@ private List<Integer> getRateLimit(List<Long> consumerIdList) {
     List<Integer> list = new ArrayList<>(consumerIdList.size());
     for (Long consumerId : consumerIdList) {
       ConsumerToken consumerToken = consumerTokenRepository.findByConsumerId(consumerId);
-      Integer rateLimit = consumerToken.getRateLimit();
+      Integer rateLimit = consumerToken != null ? consumerToken.getRateLimit() : 0;
       list.add(rateLimit);
     }