"Date" is inferred as string when specified as one of multiple possible prop types

[HusamElbashir]

Version

3.2.8

Reproduction link

codesandbox.io

Steps to reproduce

Define props

{
  props: {
    date: [Date, Number]
  },
  setup(props) {
    // type is string | number
    props.date 
  }

What is expected?

props.date should be of type Date | number

What is actually happening?

props.date is of type string | number

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This is likely related to #2668

[webfansplz]

i think have the same problem with defineProps, so I mentioned another PR to fixed it