test(e2e): add IP pool sync period test

[l1b0k]

• Add end-to-end test for IP pool sync period functionality
• Cover scenarios for releasing idle IPs and preheating IPs
• Verify IP release behavior with different sync period configurations
• Ensure proper cleanup and restoration of original configuration

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 44.57%. Comparing base (23cef2a) to head (9d4608a).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #871      +/-   ##
==========================================
+ Coverage   44.56%   44.57%   +0.01%     
==========================================
  Files         130      130              
  Lines       18984    18984              
==========================================
+ Hits         8460     8463       +3     
+ Misses       9630     9628       -2     
+ Partials      894      893       -1     

Flag	Coverage Δ
unittests	44.57% <ø> (+0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ 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.