fix: Unwrap double-wrapped JSON-RPC errors

[FrederikBolding]

A Snap may return a double-wrapped JSON-RPC error if it uses a JSON-RPC method that throws. In that case we currently do not unwrap it properly but instead return an error without a stack trace, this makes it unreadable in snaps-jest and is just generally not what we want to do. This PR unwraps this type of error to supply the stack trace.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 98.16%. Comparing base (323ac42) to head (b837428).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #3432   +/-   ##
=======================================
  Coverage   98.16%   98.16%           
=======================================
  Files         402      402           
  Lines       11116    11123    +7     
  Branches     1755     1759    +4     
=======================================
+ Hits        10912    10919    +7     
  Misses        204      204           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.