fix(接口测试): 修复接口定义path无法编辑的缺陷

--bug=1019649 --user=王孝刚 [接口测试]github#19718接口定义，创建接口，无法输入URL
https://www.tapd.cn/55049933/s/1296548

api-test/frontend/src/business/definition/components/complete/EditCompleteHTTPApi.vue

@@ -910,7 +910,7 @@ export default {
       this.basisData.caseTotal = 0;
     }
     this.httpForm = JSON.parse(JSON.stringify(this.basisData));
-    if (this.basisData.request) {
+    if (this.basisData.request && this.basisData.id) {
       this.httpForm.path = this.basisData.request.path;
       this.httpForm.method = this.basisData.request.method;
     }