fix(VOtpInput): form data support

[johnleider]

Motivation and Context

reference: https://discord.com/channels/340160225338195969/660898563139567625/1136629895330533406

Markup:

<template>
  <v-app>
    <div class="ma-4 pa-4">
      <form id="form" ref="form">
        <v-otp-input v-model="model" name="otp" @input="onInput" />
      </form>
    </div>
  </v-app>
</template>

<script setup>
  import { ref } from 'vue'

  const form = ref()
  const model = ref('')

  function onInput () {
    const news = new FormData(form.value)

    console.log(news.get('otp'))
  }
</script>

[KaelWD]

input type="hidden"?

[KaelWD]

Wrong branch?