Dashboard: Remove unused files (#7409)

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## PR-Codex overview
This PR focuses on the removal of several unused asset files and CSS modules from the `apps/dashboard` directory, streamlining the project's file structure.

### Detailed summary
- Deleted `misc.svg` from `apps/dashboard/public/assets/support/`
- Deleted `engine.png` from `apps/dashboard/public/assets/support/`
- Deleted `engine.png` from `apps/dashboard/public/assets/og-image/`
- Deleted `account.svg` from `apps/dashboard/public/assets/support/`
- Deleted `wallets.png` from `apps/dashboard/public/assets/support/`
- Deleted `contracts.png` from `apps/dashboard/public/assets/support/`
- Deleted `contracts.png` from `apps/dashboard/public/assets/og-image/`
- Deleted `engine.png` from `apps/dashboard/public/assets/product-icons/`
- Deleted `contracts.png` from `apps/dashboard/public/assets/landingpage/`
- Deleted `wallets.png` from `apps/dashboard/public/assets/product-icons/`
- Deleted `contracts.png` from `apps/dashboard/public/assets/product-icons/`
- Deleted `partner-logo.module.css` from `apps/dashboard/src/components/partners/`
- Deleted `categories.module.css` from `apps/dashboard/src/components/homepage/category/`

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<!-- This is an auto-generated comment: release notes by coderabbit.ai -->

## Summary by CodeRabbit

- **Style**
  - Removed custom styles for homepage category components, affecting layout, interactivity, and responsiveness.
  - Removed marquee animation and spacing styles for partner logo elements.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Author: MananTank