CP/DP Split: Add ability to set loadBalancerClass for load balancer Service

[bjee19]

Proposed changes

Add ability to set loadBalancerClass for load balancer Service

Problem: We would like the ability to specify the loadBalanacerClass field on a load balancer service.

Solution: Add ability to set loadBalancerClass for load balancer Service.

Testing: Manually tested that deploying NGF with the nginx.service.loadBalancerClass Helm flag would correctly set the field. Also tested that modifying the NginxProxy resource would set the loadBalancerClass when the service was re-created (the field can only be set upon creation).

Closes #3303

Checklist

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• 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 86.74%. Comparing base (5084be8) to head (92219d5).

Additional details and impacted files

@@                         Coverage Diff                         @@
##           change/control-data-plane-split    #3319      +/-   ##
===================================================================
- Coverage                            86.77%   86.74%   -0.04%     
===================================================================
  Files                                  128      128              
  Lines                                14712    14715       +3     
  Branches                                62       62              
===================================================================
- Hits                                 12766    12764       -2     
- Misses                                1806     1810       +4     
- Partials                               140      141       +1     

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