fix(VSnackbar): handle pointerleave event after transition ends

[huynhtehoa]

Description

fixes #20306

• Problem: When hovering over SnackBar, isHovering is truthy as expected but closing SnackBar does not fire onPointerLeave => isHovering is still truthy after the component is closed.
  And due to this condition !isHovering && <VProgressLinear> from VSnackBar.tsx:239, the ProgressBar does not appear when reopening the SnackBar.

• Cause: I found that this causes by the transition duration/delay from MaybeTransition in VOverlay. Therefore, I think that hover state should be correctly handled after the transition ends, which is addressed in this PR.

Markup:

I reuse the example from #20306

<template>
  <div class="text-center">
    <v-btn color="orange-darken-2" @click="snackbar = true">
      Open Snackbar
    </v-btn>

    <v-snackbar v-model="snackbar" :timeout="timeout" timer>
      {{ text }}

      <template v-slot:actions>
        <v-btn color="blue" variant="text" @click="snackbar = false">
          Close
        </v-btn>
      </template>
    </v-snackbar>
  </div>
</template>

<script>
  export default {
    data: () => ({
      snackbar: false,
      text: 'My timeout is set to 2000.',
      timeout: 2000,
    }),
  }
</script>