[DOCS] License level required (#160638)

## Summary

The pattern analysis feature is a Platinum subscription feature in
technical preview, which is now called out in the warning at the top of
the page. Otherwise users cannot follow the instructions on the page as
the options are not visible.

<img width="827" alt="Screenshot 2023-06-27 at 15 12 16"
src="https://github.com/elastic/kibana/assets/61687663/9d9fc713-6640-4e41-9003-dd080f5fe746">

### Checklist

Relates to and closes: #159170

docs/discover/log-pattern-analysis.asciidoc

@@ -1,7 +1,7 @@
 [[run-pattern-analysis-discover]]
 == Run a pattern analysis on your log data
 
-preview::[]
+preview::["This functionality is in technical preview, requires a link:https://www.elastic.co/subscriptions[Platinum subscription], and may be changed or removed in a future release. Elastic will apply best effort to fix any issues, but features in technical preview are not subject to the support SLA of official GA features."]
 
 include::../user/ml/index.asciidoc[tag=log-pattern-analysis-intro]
 Log pattern analysis works on every text field.