WebTorrent should adapt to dark/light mode settings

[stephendonner]

Description

WebTorrent should adapt to dark/light mode settings

Steps to Reproduce

1. install 1.44.26
2. launch Brave
3. set Brave colors to Dark
4. load https://webtorrent.io/free-torrents
5. click on any torrent or magnet link

Actual result:

Expected result:

The WebTorrent content should be Brave-colors aware, and adapt to Dark or Light modes

Reproduces how often:

100%

Brave version (brave://version info)

Brave	1.44.26 Chromium: 104.0.5112.81 (Official Build) nightly (x86_64)
Revision	5b7b76419d50f583022568b6764b630f6ddc9208-refs/branch-heads/5112@{#1309}
OS	macOS Version 13.0 (Build 22A5311f)

cc @fallaciousreasoning @aguscruiz

[fallaciousreasoning]

I'm happy to work on this if we can get a UX mock together 😄

[aguscruiz]

Added a mockup here @stephendonner @fallaciousreasoning
https://www.figma.com/file/wWRDxRJFw04gLPahfAjUrO/Desktop-WebTorrent?node-id=103%3A17994

There are some minor updates too, nothing in terms of actual user experience, but visual updates to make the design be in line with the Design system.

[fallaciousreasoning]

Woohoo! New design looks great. All right, I'll try and jump on this later this week 😄

[MadhaviSeelam]

Verification PASSED using

Brave | 1.44.70 Chromium: 105.0.5195.68 (Official Build) beta (64-bit)
-- | --
Revision | ad13e82529051bac6a0e65f455e6d7a1e5fd7938-refs/branch-heads/5195@{#903}
OS | Windows 11 Version 21H2 (Build 22000.856)

Verified using original STR #24498 (comment)

Confirmed WebTorrent pages adapted to dark/light mode settings and pages matched to new Figma designs.

Dark

Before Download	Downloading

Light

Before download	Downloading