Update keycloak-setup.md for Keycloak > 18

[mkingst]

Proposed changes

Problem: To configure OpenID Connect with Keycloak for NIM authentication, there are new instructions for Keycloak >18 due to UI changes on the latest version.

Solution: We added those new steps in the documentation.

Testing: Instructions validated and tested by dev and qe

Checklist

Before creating a PR, run through this checklist and mark each as complete.

• I have read the contributing guidelines

• I have signed the F5 Contributor License Agreement (CLA)

• If applicable, I have added tests that prove my fix is effective or that my feature works

• If applicable, I have checked that any relevant tests pass after adding my changes

• I have updated any relevant documentation (README.md and CHANGELOG.md)

• 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

• If the change involves:

  • Code
  • Anything that resembles Personally identifying information (PII)
    • Make sure to use placeholders such as <username> in place of PII
  • URLs (watch for typosquatting)
  • Significant new/revised content

  In these cases, the change will require at least two (2) approvals before merging

[github-actions]

🎉 Thank you for your contribution! It appears you have not yet signed the F5 Contributor License Agreement (CLA), which is required for your changes to be incorporated into an F5 Open Source Software (OSS) project. Please kindly read the F5 CLA and reply on a new comment with the following text to agree:

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I have hereby read the F5 CLA and agree to its terms

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1 out of 2 committers have signed the CLA.
✅ (travisamartin)[https://github.com/travisamartin]
❌ @mkingst
_{You can retrigger this bot by commenting recheck in this Pull Request. Posted by the CLA Assistant Lite bot.}

[github-actions]

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[mkingst]

Looks good. Thank you!