[PM-31980] Fix passkeys on some browsers by fixing JSON parsing

[Darkness4]

🎟️ Tracking

Closes #6463
Closes PM-31597

📔 Objective

Fix JSON parsing by removing comma, which caused passkeys to stop working on some browsers.

Regression introduced with #6299 (PM-30260).

Sorry if I shortcut some processes, but the fix is pretty short.

Tested on Fennec. If you close my PR to develop a long-term solution (adding some tests), I don't mind.

[CLAassistant]

All committers have signed the CLA.

[bitwarden-bot]

Thank you for your contribution! We've added this to our internal tracking system for review.
ID: PM-31980
Link: https://bitwarden.atlassian.net/browse/PM-31980

Details on our contribution process can be found here: https://contributing.bitwarden.com/contributing/pull-requests/community-pr-process.

[github-actions]

Checkmarx One – Scan Summary & Details – 2d0bbd4a-e1bf-461b-82da-c13a2aa466f4

Great job! No new security vulnerabilities introduced in this pull request

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 86.30%. Comparing base (4d31dcc) to head (ee69a69).
⚠️ Report is 4 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6502      +/-   ##
==========================================
- Coverage   86.36%   86.30%   -0.06%     
==========================================
  Files         767      780      +13     
  Lines       56045    56378     +333     
  Branches     8152     8154       +2     
==========================================
+ Hits        48405    48659     +254     
- Misses       4800     4879      +79     
  Partials     2840     2840              

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