fix(测试跟踪): 同步Jira缺陷后台报错

--bug=1018285 --user=陈建星 【测试跟踪】集成jira缺陷模板后同步缺陷后台日志报空指针 https://www.tapd.cn/55049933/s/1265409

test-track/backend/src/main/java/io/metersphere/service/issue/platform/JiraPlatform.java

@@ -915,6 +915,9 @@ public class JiraPlatform extends AbstractIssuePlatform {
                             && !msAttachmentsName.contains(filename)) {
                         try {
                             byte[] content = jiraClientV2.getAttachmentContent(attachment.get("content").toString());
+                            if (content == null) {
+                                continue;
+                            }
                             FileAttachmentMetadata fileAttachmentMetadata = attachmentService.saveAttachmentByBytes(content, AttachmentType.ISSUE.type(), issue.getId(), filename);
                             AttachmentModuleRelation attachmentModuleRelation = new AttachmentModuleRelation();
                             attachmentModuleRelation.setAttachmentId(fileAttachmentMetadata.getId());