Support mixed externalname and local services in single route (#4188)

[ciarams87]

Proposed changes

Cherry-pick of #4188

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 #ISSUE

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

❌ Patch coverage is 89.65517% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 86.12%. Comparing base (eeaaedb) to head (4ca43b4).
⚠️ Report is 1 commits behind head on release-2.2.

Files with missing lines	Patch %	Lines
internal/controller/nginx/config/servers.go	78.57%	2 Missing and 1 partial ⚠️

Additional details and impacted files

@@               Coverage Diff               @@
##           release-2.2    #4218      +/-   ##
===============================================
+ Coverage        86.11%   86.12%   +0.01%     
===============================================
  Files              131      131              
  Lines            14230    14248      +18     
  Branches            74       74              
===============================================
+ Hits             12254    12271      +17     
- Misses            1774     1775       +1     
  Partials           202      202              

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