Remove k8s API access from NGINX pod

[sjberman]

Problem: The init container in the NGINX pod needed k8s API access for NGINX Plus licensing purposes. However, this data could be provided by the control plane without the init container needing the API access. For security reasons, the NGINX pod shouldn't have any access to the API.

Solution: Remove API access and provide the necessary data directly to the pod.

Testing: Verified that the API service account token no longer exists in the data plane pod.

Closes #4344

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.

Removed k8s API access from the NGINX data plane pod.

[codecov]

Codecov Report

❌ Patch coverage is 73.33333% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 86.11%. Comparing base (cc80ed5) to head (cdad526).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
cmd/gateway/commands.go	0.00%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4368      +/-   ##
==========================================
- Coverage   86.11%   86.11%   -0.01%     
==========================================
  Files         132      132              
  Lines       14344    14343       -1     
  Branches       35       35              
==========================================
- Hits        12352    12351       -1     
+ Misses       1789     1787       -2     
- Partials      203      205       +2     

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