Updates qRadar BB rules warning for Automatic Migration (#5207)

Fixes elastic/docs-content-internal/issues/771

The way QRadar BB rules are handled in automatic migration for 9.4 and
serverless has improved vs. 9.3. This PR adds an applies switch to
describe the behavior in each version

## Generative AI disclosure
1. Did you use a generative AI (GenAI) tool to assist in creating this
contribution?
- [ ] Yes  
- [x] No  
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Author: benironside

solutions/security/get-started/automatic-migration.md

@@ -194,10 +194,15 @@ This section describes the **Translated dashboards** page's interface and the da
 :screenshot:
 ::::
 
-:::{admonition} Important warning for QRadar "BB" rules
-:applies_to: stack: preview =9.3
-In the technical preview of QRadar rule migration, QRadar Building Block rules can appear in QRadar migrations. You can identify them by their `BB:` prefix. You should not enable these rules, because they will generate noisy alerts. If you do enable them, we recommend you delete them.
-:::
+:::::{admonition} Important information for QRadar "BB" rules
+
+- {applies_to}`stack: preview =9.3`
+QRadar Building Block rules can appear in QRadar migrations. You can identify them by their `BB:` prefix. You should not enable these rules, because they will generate noisy alerts. If you do enable them, we recommend you delete them.
+
+- {applies_to}`serverless: preview`{applies_to}`stack: preview 9.4+`
+Building block rule logic is included automatically in translated rules. No action is required.
+
+:::::
 
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