fix(VSlideGroup): add display none to immediate child

[tanmoyopenroot]

fix #10310

Description

Motivation and Context

Instead of adding display: none to any child it should add to its immediate child

How Has This Been Tested?

visually

Markup:

<template>
  <v-app>
    <v-container>
      <v-card width="800">
        <v-slide-group :show-arrows="true">
          <v-slide-item
            v-for="n in 2"
            :key="n"
          >
            <v-card
              color="accent"
              class="ma-1"
              width="200"
            >
              <v-slide-group :show-arrows="true">
                <v-slide-item
                  v-for="item in items"
                  :key="item"
                >
                  {{ item }}
                </v-slide-item>
              </v-slide-group>
            </v-card>
          </v-slide-item>
        </v-slide-group>
      </v-card>
    </v-container>
  </v-app>
</template>

<script>
  export default {
    data: () => ({
      //
      items: [
        'hello',
        'there',
        'cat',
        'dog',
        'train',
        'mixer',
        'friend',
        'bobcat',
        'marker',
      ],
    }),
  }
</script>

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Improvement/refactoring (non-breaking change that doesn't add any features but makes things better)

Checklist:

• The PR title is no longer than 64 characters.
• The PR is submitted to the correct branch (master for bug fixes and documentation updates, dev for new features and backwards compatible changes and next for non-backwards compatible changes).
• My code follows the code style of this project.
• I've added relevant changes to the documentation (applies to new features and breaking changes in core library)