[MOL-22572][RP] feat: add mobile, tablet-vertical and desktop icons

[rajitha-gov]

Type 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 apis or functionality to change)
• Documentation (change to documentation, comments or API descriptions)
• Tests (improvements to unit tests or E2E tests)
• Other (technical improvements, refactoring, or changes that don't fall into the above categories)

Description of changes

• Link to ticket
• Link to Figma
• Add mobile, tablet-vertical and desktop icons for the LifeSG preview banner viewport toggle. Each Figma component set ships Fill=No and Fill=Yes variants, so both are included to match the existing phone / tablet convention:
  • MobileIcon, MobileFillIcon
  • TabletVerticalIcon, TabletVerticalFillIcon
  • DesktopIcon, DesktopFillIcon
• SVGs were exported directly from Figma into assets/ and components generated with npm run generate-icons (fills replaced with currentColor)
• Icons registered in stories/icon/data.tsx so they appear in the Storybook icon collection
• Bump version to v1.22.0

Checklist

• Changes follow the project guidelines in CONTRIBUTING.md