Updated deprecated nginx ingress controller instructions

What does this MR do and why?

While setting up Auto DevOps with GKE, the nginx ingress controller commands are deprecated. I have corrected this issue with updated commands. If left alone, the existing documentation will lead to a crash-loop in GKE, however, the user is still able to retrieve the external IP of the ingress controller pod and continue with GKE integration, leaving users confused.

Screenshots or screen recordings

There are no UI changes.

How to set up and validate locally

N/A

MR acceptance checklist

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