Fix staticcheck linter issues in k8s, nginx packages

[jjngx]

Proposed changes

This PR fixes linting issues in the k8s and nginx packages reported by staticcheck (errors and double imports)

$ staticcheck internal/k8s/*.go

internal/k8s/controller.go:3563:13: error strings should not be capitalized (ST1005)
internal/k8s/controller_test.go:21:2: package "k8s.io/api/core/v1" is being imported more than once (ST1019)
        internal/k8s/controller_test.go:22:2: other import of "k8s.io/api/core/v1"
internal/k8s/handlers.go:542:17: error strings should not be capitalized (ST1005)
...
internal/k8s/status.go:12:2: package "github.com/nginxinc/kubernetes-ingress/pkg/apis/configuration/v1" is being imported more than once (ST1019)
        internal/k8s/status.go:13:2: other import of "github.com/nginxinc/kubernetes-ingress/pkg/apis/configuration/v1"
...
internal/k8s/task_queue.go:176:19: error strings should not be capitalized (ST1005)

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

[codecov-commenter]

Codecov Report

Merging #3107 (325074a) into main (d24bd22) will decrease coverage by 0.08%.
The diff coverage is 14.28%.

❗ Current head 325074a differs from pull request most recent head 0c81f0a. Consider uploading reports for the commit 0c81f0a to get more accurate results

@@            Coverage Diff             @@
##             main    #3107      +/-   ##
==========================================
- Coverage   52.49%   52.41%   -0.09%     
==========================================
  Files          58       58              
  Lines       16033    15997      -36     
==========================================
- Hits         8417     8385      -32     
+ Misses       7338     7336       -2     
+ Partials      278      276       -2     

Impacted Files	Coverage Δ
internal/k8s/task_queue.go	0.00% <0.00%> (ø)
internal/nginx/manager.go	0.00% <0.00%> (ø)
internal/nginx/utils.go	0.00% <0.00%> (ø)
internal/k8s/controller.go	11.00% <14.28%> (ø)
internal/k8s/status.go	33.27% <20.00%> (ø)
internal/k8s/handlers.go	6.83% <100.00%> (ø)
internal/k8s/validation.go	93.31% <0.00%> (-0.50%)	⬇️
internal/k8s/configuration.go	95.76% <0.00%> (+0.36%)	⬆️

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