fix(VFab, VFooter): avoid error when changing app prop

[J-Sek]

fixes #20398

• we should not scope composable with dependency on provide() and vm

Note:

• reverts 0bfaf12... TBD

Markup:

<template>
  <v-app theme="dark">
    <v-footer :app="isAppFooter" color="grey"> Test </v-footer>
    <v-fab :app="isAppFab" color="grey" icon="mdi-cow" />
    <v-main>
      <v-btn @click="isAppFooter = !isAppFooter">toggle footer ({{ isAppFooter }})</v-btn>
      <v-btn @click="isAppFab = !isAppFab">toggle fab ({{ isAppFab }})</v-btn>
    </v-main>
  </v-app>
</template>

<script setup lang="ts">
  import { ref } from 'vue'

  const isAppFooter = ref(true)
  const isAppFab = ref(true)
</script>