[TC][Sourse block] Verify horizontal scroll when more than 3 category cards are displayed

[NataliaGumenchyk]

Priority: Medium

Preconditions

1. The user is on the page https://historycode.online/vasyl-stus
2. Page contains 4 or more source category cards (e.g. “Історії”, “Фільми”, “Фото”, “Архів”, etc.).

Steps to reproduce

1. Scroll down to the "Джерела" (Sources) block Expected Result: The source block is visible and contains >3 cards
2. Observe the cards layout Expected Result: Right scroll arrow is displayed
3. Click the right scroll arrow once Expected Result: Cards shift left and new cards appear in view
4. Click the left scroll arrow Expected Result: Cards return to the previous position

Expected result If there are more than 3 cards -arrows appears. Right arrow is active and left arrow is default. After scrolling left arrow becomes active.

User story: https://github.com/ita-social-projects/StreetCode/issues/41

Related bug: