Adding styling to the scrollbars, according to theme of the web app

[Nirmitjatana]

Is your feature request related to a problem? Please describe.
White scrollbars look odd with respect to the current theme of the website.

Describe the solution you'd like
We can add styling to the scroll bar for both dark mode and light mode.

Describe alternatives you've considered
The solution is pretty straightforward, and shouldn't require alternatives

Additional context
Styling can be added to both side and overflow scroll bar

[shuklaayush]

Duplicates #2158