feat(VCombobox): add trim-values prop

[J-Sek]

fixes #14874

Could be a default in v5.0, depending on reception and feedback. Original issue did not attract too much attention.

<template>
  <v-app theme="dark">
    <v-container max-width="500">
      <v-alert class="mb-4"><pre>{{ values }}</pre></v-alert>
      <v-combobox
        v-model="values"
        :items="['California', 'Colorado', 'Florida', 'Georgia', 'Texas', 'Wyoming']"
        label="Combobox"
        chips
        closable-chips
        multiple
		trim-values
      />
    </v-container>
  </v-app>
</template>

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

  const values = shallowRef([])
</script>