Fix Issue #4334: Add GitHub icon linking to git repository

[foxzhang1224]

🔧 What has been changed? This PR adds a GitHub icon next to each project name on the homepage that links to its github repository page. Clicking the GitHub icon takes the user directly to the root GitHub repository of the project (e.g., https://github.com/user/repo).

🎯 Why This Matters Many projects listed on up-for-grabs.net currently link to a GitHub label like: https://github.com/user/repo/issues/labels/good-first-issue

Therefore, it there could be a way to directly link the user to the GitHub repository, a quicker navigation could be offered to explore the full project on a technical term, especially to those potential contributor.

🛠️ How It Works

1. Extracted the repository root by splitting the project.upforgrabs.link and joining the first 5 segments: project.upforgrabs.link.split('/').slice(0, 5).join('/') Since we couldn't directly get the url of many projects, parsing the link to its labelled issue could lead us to the main repo page.

2. Conditionally rendered the icon only if project.upforgrabs.link is defined

3. Added the icon using a github SVG from Simple Icons cdn

<img src="https://cdn.jsdelivr.net/npm/simple-icons@v10/icons/github.svg" alt="GitHub" width="20" height="20" style="vertical-align: middle;" />

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