refactor(VSnackbar): remove redundant wrapper element

[KaelWD]

Description

Allows for content-class="elevation-xx"

Markup:

<template>
  <div class="text-center ma-2">
    <v-btn
      @click="snackbar = true"
    >
      Open Snackbar
    </v-btn>
    <v-snackbar
      v-model="snackbar"
      timeout="-1"
    >
      {{ text }}

      <template #actions>
        <v-btn
          color="pink"
          variant="text"
          @click="snackbar = false"
        >
          Close
        </v-btn>
      </template>
    </v-snackbar>
  </div>
</template>

<script>
  export default {
    data: () => ({
      snackbar: false,
      text: `Hello, I'm a snackbar`,
    }),
  }
</script>