Improve unit/integration tests coverage for web code

[souhaib-benbouzid]

Description

if you:

• go to ./web folder
• then run yarn test:cov:watch inside it
• then open ./web/coverage/lcov-report/index.html file in your browser

you will see that some directories are marked as red, which means test coverage is below 80%. you can also see the same results in codecov.io

In this task we will make sure that all dirs are marked green ✅.

Check List

Integration tests for pages:

1. add integration test for ./web/src/apps/main/pages/landing.
2. add integration test for ./web/src/apps/main/pages/faq. (de4ae32)
3. add integration test for ./web/src/apps/main/pages/not-found.
4. add integration test for ./web/src/apps/main/pages/projects.
5. add integration test for ./web/src/apps/main/pages/articles.
6. add integration test for ./web/src/apps/main/pages/learn.

Unit tests for components:

1. add unit test for ./web/src/components/link-v2.
2. add unit test for ./web/src/components/loading.
3. add unit test for ./web/src/apps/main/components/authors.
4. add unit test for ./web/src/apps/main/components/card.
5. add unit test for ./web/src/apps/main/components/contributors.
6. add unit test for ./web/src/apps/main/components/footer. (6fec148)
7. add unit test for ./web/src/apps/main/components/markdown.
8. add unit test for ./web/src/apps/main/components/navbar.
9. add unit test for ./web/src/apps/main/components/sidebar.
10. add unit test for ./web/src/apps/main/components/speed.
11. add unit test for ./web/src/apps/main/components/theme.

Additional Comments

Please create new PR for each task.

Also, it would be great for transparency if you comment below which task you want to take up.