feat(VCombobox): scroll to first item on search result (#20572)

[jcjp]

Description

• Fixes: [Feature Request] [V-Combobox] scroll to the item which will automatically selected if auto-select-first is true #20572
• Issue is the first item auto selected is hidden by default when you double click on the initial value "foo" and then type "fi" on the input.
  • Actual result: fi2 onwards shown and fi1 is hidden.
  • Expected result: fi1 should still be displayed

Markup:

<template>
  <v-combobox
    auto-scroll
    v-model="value"
    :items="items"
    label="Default"
    auto-select-first
  />
</template>

<script>
  export default {
    data: () => ({
      items: [
        'bar',
        'buzz',
        'fi1',
        'fi2',
        'fi3',
        'fi4',
        'fi5',
        'fi6',
        'fizz',
        'foo',
      ],
      value: 'foo',
    }),
  }
</script>

[johnleider]

Feature requests should go to dev branch.

[jcjp]

Feature requests should go to dev branch.

Thanks John pointed to dev now.

[Copilot]

Pull Request Overview

This PR implements a fix for issue #20572 by ensuring that the first search result item is visible in the VCombobox component.

• Automatically scrolls to the first item after a search in single selection mode.
• Updates the VCombobox to call the virtual scroll component's scrollToIndex method.