Fix some of the NFR tests to reduce error logs and pipeline failures

[salonichf5]

Proposed changes

Write a clear and concise description that helps reviewers understand the purpose and impact of your changes. Use the
following format:

Problem: NFR tests had errors and had pipeline failures.

Solution: I have tried to add fixes for some of the errors and fix the pipeline failures

This PR also adds --server-side flag to gateway API crd installation

Testing: Re ran tests locally to ensure they pass

What's excluded - Not investigating longevity tests because the NGINX agent bug should solve issues around it that's being monitored and investigated of by another teammate.

Please focus on (optional): If you any specific areas where you would like reviewers to focus their attention or provide
specific feedback, add them here.

Closes #3728
Closes #3796

Checklist

Before creating a PR, run through this checklist and mark each as complete.

• I have read the CONTRIBUTING doc
• I have added tests that prove my fix is effective or that my feature works
• I have checked that all unit tests pass after adding my changes
• I have updated necessary documentation
• I have rebased my branch onto main
• I will ensure my PR is targeting the main branch and pulling from my branch from my own fork

Release notes

If this PR introduces a change that affects users and needs to be mentioned in the release notes,
please add a brief note that summarizes the change.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 86.82%. Comparing base (826319f) to head (9647d52).
⚠️ Report is 4 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3827      +/-   ##
==========================================
+ Coverage   86.81%   86.82%   +0.01%     
==========================================
  Files         128      128              
  Lines       16500    16500              
  Branches       62       62              
==========================================
+ Hits        14324    14326       +2     
+ Misses       1997     1996       -1     
+ Partials      179      178       -1     

☔ 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.

[shaun-nx]

Nice work @salonichf5 🎉