Don't track stack when in performance test mode

[hintse]

In a performance test, you probably don't need the stack information for debugging purposes. Instead, you'll probably be queuing a lot of events, which can be slow if we keep track of the stack info.

[github-actions]

Test Results

618 tests  +13   610 ✅ +13   7m 12s ⏱️ +2s
  1 suites ± 0     8 💤 ± 0 
  1 files   ± 0     0 ❌ ± 0 

Results for commit 3907f36. ± Comparison against base commit 580acfc.

♻️ This comment has been updated with latest results.

[codecov]

Codecov Report

❌ Patch coverage is 90.56604% with 15 lines in your changes missing coverage. Please review.
✅ Project coverage is 84.83%. Comparing base (580acfc) to head (3907f36).
⚠️ Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
csp_gateway/testing/harness.py	57.14%	14 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #247      +/-   ##
==========================================
+ Coverage   84.57%   84.83%   +0.26%     
==========================================
  Files         138      138              
  Lines       14025    14151     +126     
  Branches     1395     1396       +1     
==========================================
+ Hits        11861    12005     +144     
+ Misses       1729     1706      -23     
- Partials      435      440       +5     

☔ 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.