fix: use official kubectl image for CRD installer job

[sanmesh-kakade]

Summary

• Cherry-pick of fix from nginx-fabric-legacy branch (PR fix: use official kubectl image for CRD installer job #514)
• bitnami/kubectl:1.31.4 does not exist on Docker Hub, causing ImagePullBackOff on the gateway API CRD installer job
• Switched to the official distroless image registry.k8s.io/kubectl:v1.31.4
• Updated command/args since the distroless image has no /bin/sh — invokes kubectl directly with separate args

Test plan

• Verified manually on cluster: job completes successfully with the new image
• Confirm Terraform plan shows only the image and command change

🤖 Generated with Claude Code

Summary by CodeRabbit

• Chores
  • Updated Kubernetes Gateway API installer to use the official Kubernetes registry container image instead of a third-party source.
  • Refined installer command execution for Kubernetes Gateway API CRD deployment.

[coderabbitai]

Walkthrough

Updated Kubernetes Job installer resource to use official registry.k8s.io kubectl image instead of bitnami, changed container execution from shell to direct kubectl command, and restructured arguments from shell string to array format.

Changes

Cohort / File(s)	Summary
Kubectl Container Configuration modules/gateway_api_crd/k8s/1.0/main.tf	Updated container image from bitnami/kubectl:1.31.4 to registry.k8s.io/kubectl:v1.31.4, changed command from shell execution ["/bin/sh", "-c"] to direct kubectl invocation ["kubectl"], and restructured arguments from single shell string to split array format ["apply", "--server-side", "-f", local.install_url].

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately captures the main change: switching to the official kubectl image for the CRD installer job, which is the core purpose of this pull request.
Description check	✅ Passed	The description covers the key aspects (summary, root cause, solution, testing) but is missing several required template sections like Related issues, Type of change checklist, and full Checklist items.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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✨ Finishing touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch nginx-gateway-fabric-legacy-to-master

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No actionable comments were generated in the recent review. 🎉

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