Remove Logstash Kubernetes from published docs

[karenzone]

Fixes: elastic/logstash#15863

Updates conf.yaml to remove Logstash on Kubernets from docs landing page.

Logstash on ECK is the preferred path forward with Logstash on Kubernetes.

[github-actions]

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[karenzone]

@lcawl, here's the change we discussed in a recent 1:1.

[bmorelli25]

@karenzone I think we have the BK builds fixed. Can you rebase this PR to pull in the latest changes pls

[karenzone]

@bmorelli25 I'm not sure I did the rebase correctly. I see where I forced pushed, but the PR is still showing only the original commit. It was enough to kick off a new build, but it'll likely still fail if I haven't included the latest BK changes.

[bmorelli25]

I see where I forced pushed, but the PR is still showing only the original commit.

That's expected! Everything looks good to me 😄

preview looks good too

[karenzone]

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