disable webusb and bluetooth API explicitly

[diracdeltas]

disable webusb and bluetooth API

neither are supported, but this will cause sites that check whether
they're supported to know more reliably that they aren't supproted.

fix https://github.com/brave/browser-laptop/issues/13374

fix #13374

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. (Ask a Brave employee to help if you cannot access this document.)

Test Plan:

1. go to any site and open page console.
2. navigator.usb should be undefined
3. navigator.bluetooth should be undefined

Reviewer Checklist:

• Request a security/privacy review as needed if one was not already requested.

Tests

• Adequate test coverage exists to prevent regressions
• Tests should be independent and work correctly when run individually or as a suite ref
• New files have MPL2 license header

[evq]

lgtm, test plan passes

[diracdeltas]

master: 5143bd3
0.23.x: cfa51af
0.22.x: 768bfd6

[btlechowski]

Verified on Windows 7 x64

• 0.22.7 8bb7e77
• libchromiumcontent: 65.0.3325.181
• muon: 5.1.1