[Desktop] Support fingerprint webauthn on macOS

Description

For publishers we received a request from @tomlowenthal to implement webauthn as a sign in provider. However in the current release of Brave webauthn is not supported

https://webauthn.bin.coffee https://webauthndemo.appspot.com

Actual result:

On the webauthn.bin.coffee site when you try and generate a login

Contacting token... please perform your verification gesture (e.g., touch it, or plug it in)

Note: Raw response in console.
Got error:
TypeError: Cannot read property 'response' of null

Failures: 1 TODOs: 0

Expected result:

webauthn successfully works when trying to authenticate with a fingerprint reader

Reproduces how often:

Everytime

Brave version (brave://version info)

All versions.

Test Plan

Specified here: https://github.com/brave/brave-core/pull/5539

Additional Information

Essentially think it’s related to removing credentialManager https://github.com/brave/brave-core/pull/1896

[ChadKillingsworth]

Github has now enabled this functionality and next month over a hundred banks and credit unions will have it enabled for their sites. Really need this enabled.

[kimbim]

Need this to switch to Brave!