fix(VSelect): fix hide-selected with return-object

[lzl0304]

Description

fix #19806

Markup:

<template>
  <v-switch v-model="returnObject" color="primary" label="Return Object" />
  <v-select
    v-model="select"
    :hint="`${select.state}, ${select.abbr}`"
    :items="items"
    :return-object="returnObject"
    item-title="state"
    item-value="abbr"
    label="Select"
    hide-selected
  />
</template>

<script>
  export default {
    data () {
      return {
        select: { state: 'Florida', abbr: 'FL' },
        returnObject: false,
        items: [
          { state: 'Florida', abbr: 'FL' },
          { state: 'Georgia', abbr: 'GA' },
          { state: 'Nebraska', abbr: 'NE' },
          { state: 'California', abbr: 'CA' },
          { state: 'New York', abbr: 'NY' },
        ],
      }
    },
  }
</script>