Change "join the team" button and open new Vacancies

**Environment:** OS: Windows 10
**Browser:** Google Chrome Version 116.0.5845.98
**Reproducible:** always
**Build found:** last commit from https://github.com/ita-social-projects/StreetCode_Client
E.g. "commit[[40ddfe5](https://github.com/ita-social-projects/StreetCode_Client/commit/40ddfe5478489ce2da5825e4abc21583ce001ccc)]
**Priority:** High.
**Severity:** Trivial.
**Type:** UI.

**Preconditions**

1. Go to the site main page
2. Press the "Долучитися" button

**Actual result**
On the Mainpage on the right there is a button “Долучитись”. When you click on it, a modal with 4 buttons opens - the “Долучитись до команди” button refer you to 404 page.

**Expected result**
On the Mainpage on the right there is a button “Долучитись”. When you click on it, a modal with 4 buttons opens - the “Долучитись до команди” button appears if there is at least one active vacancy. If you click on the button to go to the “Про нас” page, you need to go to the “Вакансії” section.