feat(ui): Create reusable EmptyState component for empty states

[Vivvek09]

What changes are being made and why?

Created a reusable EmptyState component for displaying consistent empty states across the UI.

This PR:

• Creates a new EmptyState component in the components folder
• Refactors existing empty states (dependencies, concurrency) to use this component
• Maintains theme support (light/dark modes)
• Ensures consistent styling and messaging across empty states

closes #5525

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How the changes have been QAed?

The component has been tested with:

1. Dependencies View:

<empty-state
    :title="$t('dependency-view.title_no_deps')"
    :description="$t('dependency-view.desc_no_deps')"
    :image="flowImage"
/>

2. Concurrency View:

<empty-state
    :title="$t('concurrency-view.title_no_limit')"
    :description="$t('concurrency-view.desc_no_limit')"
    :image="noConcurrencyImage"
/>

Translations:

{
    "dependency-view": {
        "title_no_deps": "No dependencies are set for this Flow.",
        "desc_no_deps": "Read more about <a href=\"https://kestra.io/docs/workflow-components/dependencies\" target=\"_blank\">Flow Dependencies in our documentation."
    },
    "concurrency-view": {
        "title_no_limit": "No limits are set for this Flow.",
        "desc_no_limit": "Read more about <a href=\"https://kestra.io/docs/workflow-components/concurrency\" target=\"_blank\">Concurrency Limits in our documentation."
    }
}

The images are being imported from the assets folder.

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Setup Instructions