feat: common emptystate

[shravankumar8]

Pull Request Description

Title:

feat(ui): introduce reusable EmptyState component and refactor module variants (#150)

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Description

Refactors duplicate empty-state components from multiple modules into a single shared EmptyState component. Tailored for flexibility, it supports props like image, title, subtitle, description, ctaText, onCtaClick, and an optional tutorial object.

Fixes: #150

Motivation:

• Reduces code duplication and enhances maintainability
• Ensures consistent appearance and behavior across modules
• Simplifies future enhancements (like adding secondary buttons)

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Type of Change

• 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)
• This change requires a documentation update

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How Has This Been Tested?

• Scenario A: Verified in Sources module — Empty state renders correctly with all props.
• Scenario B: Verified in Destinations and Jobs — Button actions and tutorial card work as expected.

Steps to reproduce:

1. Start the UI (make start-frontend)
2. Navigate to modules with empty state (Sources, Destinations, Jobs)
3. Confirm consistent layout, valid image and text, clickable button, and tutorial thumbnail/link

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Screenshots or Recordings

Screen.Recording.2025-08-16.at.4.46.34.PM.mov