fix path issue preventing u2f support from working on mac

[evq]

Fixes #13344

The cryptotoken extension (used for u2f support) is bundled into electron_resources.pak as part of the muon build. There is muon code which attempts to fetch extension resources from the pak if the path passed during extension load is a subdirectory of chrome::DIR_RESOURCES. Currently we use process.resourcesPath on the browser-laptop side to get the path to the chome::DIR_RESOURCES directory.

There's an issue with this on mac though, in that process.resourcesPath returns Brave.app/Contents/Resources while inside muon chome::DIR_RESOURCES actually refers to Brave.app/Contents/Frameworks/Brave Framework.framework/Resources.

This PR adds a helper function to retrieve the correct path for all platforms.

I've tested this PR on mac in dev mode as well as with a packaged build and also on linux to ensure u2f support is still working there.

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 https://demo.yubico.com/u2f?tab=register
2. Make up a username and password and click next
3. You should be prompted to plug in your u2f key
4. You will be prompted to touch the sensor on your u2f key
5. On success you can attempt login using the same username and password
6. You will be prompted to again plug in / touch the sensor on your u2f key

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

[codecov-io]

Codecov Report

Merging #13345 into master will decrease coverage by 0.54%.
The diff coverage is 42.85%.

@@            Coverage Diff             @@
##           master   #13345      +/-   ##
==========================================
- Coverage   56.54%      56%   -0.55%     
==========================================
  Files         284      282       -2     
  Lines       28658    28218     -440     
  Branches     4740     4643      -97     
==========================================
- Hits        16206    15804     -402     
+ Misses      12452    12414      -38

Flag	Coverage Δ
#unittest	56% <42.85%> (-0.55%)	⬇️

Impacted Files	Coverage Δ
js/lib/appUrlUtil.js	84.66% <42.85%> (-1.88%)	⬇️
js/stores/appStore.js	16.57% <0%> (-11.42%)	⬇️
js/lib/request.js	17.64% <0%> (-11.15%)	⬇️
app/common/state/tabUIState.js	30.69% <0%> (-7.19%)	⬇️
...p/renderer/components/tabs/content/closeTabIcon.js	35.71% <0%> (-3.91%)	⬇️
...pp/renderer/components/tabs/content/privateIcon.js	38.09% <0%> (-1.25%)	⬇️
...renderer/components/tabs/content/newSessionIcon.js	36.36% <0%> (-1.14%)	⬇️
app/browser/menu.js	51.64% <0%> (-1.07%)	⬇️
js/stores/windowStore.js	27.66% <0%> (-0.98%)	⬇️
app/common/state/tabContentState/titleState.js	73.46% <0%> (-0.89%)	⬇️
... and 25 more

[bsclifton]

Awesome job with this! Tested this change on both macOS and Windows... both worked great (nice test steps!)

[bsclifton]

master f4c2847
0.23.x 27f76a7
0.22.x b2f58eb