[DOCS] Clarify AI Assistant will spawn ML nodes (#3687)

Co-authored-by: DeDe Morton <[email protected]>
(cherry picked from commit f1e14ba)

docs/en/observability/observability-ai-assistant.asciidoc

@@ -41,6 +41,11 @@ The AI assistant requires the following:
 ** AWS Bedrock, specifically the Anthropic Claude models.
 * The knowledge base requires a 4 GB {ml} node.
 
+[IMPORTANT]
+====
+In {ecloud} or {ece}, if you have Machine Learning autoscaling enabled, Machine Learning nodes will be started when using the knowledge base and AI Assistant. Therefore using these features will incur additional costs.
+====
+
 [discrete]
 [[data-information]]
 == Your data and the AI Assistant