fix: properly diff when using legacy UI with toRender matcher

[FrederikBolding]

This fixes two problems with diff outputs when using toRender with legacy UI:

• Firstly we had flipped actual and expected causing confusing output
• Secondly we were diffing not just the content but also the rest of the response object unnecessarily

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 94.30%. Comparing base (5e6db9d) to head (3ecb733).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2432   +/-   ##
=======================================
  Coverage   94.30%   94.30%           
=======================================
  Files         437      437           
  Lines        8987     8987           
  Branches     1378     1378           
=======================================
  Hits         8475     8475           
  Misses        512      512           

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