fix(接口定义): 修复json错误格式仍可转jsonSchema的缺陷

--bug=1018522 --user=王孝刚 【接口测试】github#18661，接口请求体参数删除后，点击保存成功
，JSON-SCHEMA模式下参数实际并没有删除成功 https://www.tapd.cn/55049933/s/1269410

api-test/frontend/src/business/definition/components/body/ApiBody.vue

@@ -221,15 +221,20 @@ export default {
       });
     },
     formatChange() {
-      const MsConvert = new Convert();
 
+      const MsConvert = new Convert();
       if (this.body.format === 'JSON-SCHEMA') {
         if (this.body.raw) {
-          if (!this.body.jsonSchema) {
-            this.body.jsonSchema = MsConvert.format(JSON.parse(this.body.raw));
-          } else {
-            let data = MsConvert.format(JSON.parse(this.body.raw));
-            this.body.jsonSchema = this.deepAssign(this.body.jsonSchema, data);
+          try {
+            if (!this.body.jsonSchema) {
+              this.body.jsonSchema = MsConvert.format(JSON.parse(this.body.raw));
+            } else {
+              let data = MsConvert.format(JSON.parse(this.body.raw));
+              this.body.jsonSchema = this.deepAssign(this.body.jsonSchema, data);
+            }
+          } catch (e) {
+            this.body.format = 'JSON';
+            this.$message.error(this.$t('api_definition.body.json_format_error'));
           }
         }
       } else {

api-test/frontend/src/i18n/lang/en-US.js

@@ -14,6 +14,9 @@ const message = {
       desc: "Description",
       type: "Type",
       default_value: "Default value"
+    },
+    body: {
+      json_format_error: "JSON format error"
     }
   },
   home:{

api-test/frontend/src/i18n/lang/zh-CN.js

@@ -15,6 +15,9 @@ const message = {
       type: "类型",
       default_value: "默认值",
     },
+    body: {
+      json_format_error: "JSON格式错误",
+    }
   },
   home: {
     table: {

api-test/frontend/src/i18n/lang/zh-TW.js

@@ -15,6 +15,9 @@ const message = {
       type: "類型",
       default_value: "默認值",
     },
+    body: {
+      json_format_error: "JSON格式錯誤",
+    }
   },
   home: {
     table: {