Disable WebTorrent in Tor profile

[yrliou]

Fix brave/brave-browser#1134
Don't redirect magnet and .torrent URLs to webtorrent component extension in Tor profile so they won't use WebTorrent.
Only added tests in brave_torrent_redirect_network_delegate_helper for .torrent case but didn't add tests for IsWebtorrentEnabled change because it's quite trivial.

Submitter Checklist:

• Submitted a ticket for my issue if one did not already exist.
• Used Github auto-closing keywords in the commit message.
• Added/updated tests for this change (for new code or code which already has tests).
• Ran git rebase -i to squash commits (if needed).
• Tagged reviewers and labelled the pull request as needed.
• Request a security/privacy review as needed.
• Add appropriate QA labels (QA/Yes or QA/No) to include the closed issue in milestone

Test Plan:

manual test:

1. Click "Open Tor Window" under user's profile image and visit https://webtorrent.io/free-torrents in the tor window
2. Click a torrent file link will prompt to download the torrent file
3. Click a magnet link will prompt to ask if user wants to open his/her default external application for magnet links like below.

4. Right click a magnet link to open it in a new tab will shows the same prompt as 3 in the new tab.

unit test:
npm run test -- brave_unit_tests --filter=BraveTorrentRedirectNetworkDelegateHelperTest.*

Reviewer Checklist:

• New files have MPL-2.0 license header.
• Request a security/privacy review as needed.
• Adequate test coverage exists to prevent regressions
• Verify test plan is specified in PR before merging to source

[darkdh]

can we do something like return ui_data->GetTorProfileService() ? true : false;

[yrliou]

Sure, addressed in df81708

[darkdh]

++

[yrliou]

master: 65e87e0
0.55.x: 770075f
0.56.x: fd88e2a