feat(utabs): add badge component to UTabs

[husamMousa]

🔗 Linked issue

❓ Type of change

• 📖 Documentation (updates to the documentation or readme)
• 🐞 Bug fix (a non-breaking change that fixes an issue)
• 👌 Enhancement (improving an existing functionality)
• ✨ New feature (a non-breaking change that adds functionality)
• 🧹 Chore (updates to the build process or auxiliary tools and libraries)
• ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

📚 Description

This PR introduces a badge component to the UTabs feature. The badge is intended to provide users with visual indicators (e.g., notifications or counts) on tab elements.

Key changes include:

• Implementation of a badge element within UTabs.
• Updated styling and logic to support badge integration without impacting existing tab functionality.

📝 Checklist

• I have linked an issue or discussion.
• I have updated the documentation accordingly.

[maxsteinwand]

You can already use the default slot of UTabs to customize the label: https://ui.nuxt.com/components/tabs#default

<script setup lang="ts">
const items = [
  {
    label: 'Getting Started',
    content: 'This is the content shown for Tab1',
    badge: 20,
    icon: 'i-heroicons-information-circle'
  },
  {
    label: 'Installation',
    content: 'And, this is the content for Tab2',
    disabled: true,
  },
  {
    label: 'Theming',
    content: 'Finally, this is the content for Tab3',
    badge: 'New',
  },
];
</script>

<template>
  <UTabs :items="items" class="w-full">
    <template #default="{ item, index, selected, disabled }">
      <span>{{ item.label }}</span>
      <UBadge
        v-if="item.badge"
        class="flex-shrink-0 ms-1.5 relative rounded"
        :label="item.badge"
        size="xs"
      />
    </template>
  </UTabs>
</template>

[husamMousa]

@maxsteinwand,

Thank you for your feedback! I see that it's possible to customize the label using the default slot, as shown in your example. However, my proposed feature aims to enhance the user experience and streamline the implementation process.