必填项为空校验，valid第一次为true，再点值为false

引入FormInstance ，校验代码改为以下：

import { ElMessage, FormInstance } from 'element-plus'
const ruleFormRef = ref<FormInstance>()

const submitForm = async (formEl: FormInstance | undefined) => {
  if (!formEl) return
  await formEl.validate((valid, fields) => {
    if (valid) {
    // 校验成功
    } else {
      console.log('error submit!', fields)
    }
  })
}
const resetForm = (formEl: FormInstance | undefined) => {
  if (!formEl) return
  formEl.resetFields()
}