fix(测试用例): 关联接口取消协议列表显示问题

--bug=1044475 --user=王旭 【功能用例】用例详情-关联接口用例-取消勾选全部协议后-列表仍展示全部数据 https://www.tapd.cn/55049933/s/1562051

backend/services/api-test/src/main/java/io/metersphere/api/provider/AssociateApiProvider.java

@@ -38,6 +38,9 @@ public class AssociateApiProvider implements BaseAssociateApiProvider, BaseAssoc
 
     @Override
     public List<TestCaseProviderDTO> getApiTestCaseList(String sourceType, String sourceName, String apiCaseColumnName, TestCasePageProviderRequest testCasePageProviderRequest) {
+        if (CollectionUtils.isEmpty(testCasePageProviderRequest.getProtocols())) {
+            return new ArrayList<>();
+        }
         return extApiTestCaseMapper.listByProviderRequest(sourceType, sourceName, apiCaseColumnName, testCasePageProviderRequest, false);
     }