feat(VNumberInput): clear zero's on focus

[J-Sek]

Description

resolves #19900

I intend to include one more docs example for 0.00 once strict precision support (#20252) is merged.

Markup:

<template>
  <v-container>
    <v-number-input clear-zero clearable v-model='someValue' />
    <code>value: {{ someValue }} | {{ typeof someValue }}</code>
  </v-container>
</template>

<script setup>
  import { ref } from 'vue'
  const someValue = ref(0)
</script>