Properly fix custom paths (for quarantine fix)

[bsclifton]

Fixes #13817

Auditors: @LaurenWags, @jumde, @bridiver

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:

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

[bsclifton]

master 2eb5228
0.23.x e9b9394
0.22.x 876b8a1
0.22.x-promo 48beca4

[petemill]

0.22.x-c66 fd2eeeb