Update running-logstash-kubernetes.asciidoc

[flexitrev]

Removed technical preview language

Type of change

• doc
  -->

Release notes

[rn:skip]

What does this PR do?

Why is it important/What is the impact to the user?

change of release state

Checklist

• My code follows the style guidelines of this project
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have made corresponding change to the default configuration files (and/or docker env variables)
• I have added tests that prove my fix is effective or that my feature works

[karenzone]

Nice improvement, thank you! ❤️
Please use active voice and add punctuation (as suggested inline).

Shouldn't this be based out of main rather than 8.17?

[flexitrev]

I was going to go out of main, but it gave me an angry warning, so I was trying to be safe