[Bug] [taier-ui] 同步任务使用变量报 task params content can not be null

[caiyuyux]

Search before asking

• [X] I had searched in the issues and found no similar issues.

What happened

1.4.0 版本

场景一

同步任务向导模式，配置了系统变量，点击转化成脚本模式报异常

场景二

同步任务脚本模式，脚本中存在系统变量，任务保存失败

What you expected to happen

任务保存成功或脚本转化成功

How to reproduce

# 示例脚本
{
  "job": {
    "content": [
      {
        "reader": {
          "parameter": {
            "url": "xxx",
            "fetchSize": 1000,
            "collectionName": "AlarmType",
            "filter": "{tenantId:'system'}",
            "column": [
              {
                "name": "_id",
                "type": "string"
              },
              {
                "name": "notificationMode",
                "type": "string",
                "value": "${bdp.system.cyctime}"
              }
            ]
          },
          "name": "mongodbreader"
        },
        "writer": {
          "parameter": {
            "mode": "update",
            "postSql": [],
            "password": "xxx",
            "uniqueKey": [
              "id"
            ],
            "column": [
              {
                "name": "id",
                "type": "string"
              },
              {
                "name": "notificationMode",
                "type": "string"
              }
            ],
            "connection": [
              {
                "jdbcUrl": "xxxx",
                "table": [
                  "alarm_type"
                ]
              }
            ],
            "username": "root"
          },
          "name": "mysqlwriter"
        }
      }
    ]
  }
}

Anything else

No response

Version

v1.4

Are you willing to submit PR?

• [ ] Yes I am willing to submit a PR!

Code of Conduct

• [X] I agree to follow this project's Code of Conduct