fix(接口测试): csv上传后清空预览信息

--bug=1013355 --user=王孝刚 【接口测试】github#13766，场景变量里添加多个CVS时，预览页的信息没有及时清空
https://www.tapd.cn/55049933/s/1161591

frontend/src/business/components/api/automation/scenario/variable/EditCsv.vue

@@ -124,16 +124,25 @@
         }
         this.loading = false;
       },
+      cleanPreview() {
+        this.allData = [];
+        this.columns = [];
+        this.previewData = [];
+      },
       step(results, parser) {
-        if(this.allData.length < 500) {
+        if (this.allData.length < 500) {
           this.allData.push(results.data);
-        }else{
+        } else {
           this.showMessage = true;
         }
       },
 
       handleClick() {
-        let config = {complete: this.complete, step: this.step, delimiter: this.editData.delimiter ? this.editData.delimiter : ","};
+        let config = {
+          complete: this.complete,
+          step: this.step,
+          delimiter: this.editData.delimiter ? this.editData.delimiter : ","
+        };
         this.allData = [];
         // 本地文件
         if (this.editData.files && this.editData.files.length > 0 && this.editData.files[0].file) {

frontend/src/business/components/api/automation/scenario/variable/VariableList.vue

@@ -368,6 +368,9 @@ export default {
       this.editData = {delimiter: ",", quotedData: 'false', files: []};
       this.editData.type = this.selectType;
       this.showDelete = false;
+      if (this.editData.type === 'CSV') {
+        this.$refs.csv.cleanPreview();
+      }
       this.$refs.variableTable.cancelCurrentRow();
     },
     confirmVariable() {