fix:Lecture_Player

[ambesh333]

PR Fixes:

• 1 Added new Lecture Player Design
• 2 Added a custom scroll bar (not included in the design )
• 3 Added new reply comment design (Ui was not present in the figma design)

Resolves #[#888]

https://github.com/user-attachments/assets/51851f1a-1a98-468f-badc-300dbe9e9822

@hkirat @siinghd

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