added scroll restoration on forward/backward navigation

[KitsuneKode]

PR Fixes:

• 1 Added Scroll restoration to contents

The course content page scrolls to the top on navigation(backward/forward).
Scrolling through the same weeks of content again and again to find the video/week is just straight up annoying.
This PR fixes it, restores back to the point before navigation.

Checklist before requesting a review

• [x ] I have performed a self-review of my code
• [x ] I assure there is no similar/duplicate pull request regarding same issue

[tarun-katal]

@KitsuneKode

• isn't ref logic redundant?
• also is there any use of { scroll: false } as we're using window.scrollTo logic in useEffect anyway?
  it seemed to work fine w/o them too..