Clarify scope of customize built in policies tutorial

Updated the title to include 'agent data stream' for clarity.

based on elastic/elasticsearch#116453

Author: shainaraskas

manage-data/lifecycle/index-lifecycle-management/tutorial-customize-built-in-policies.md

@@ -7,7 +7,7 @@ products:
   - id: elasticsearch
 ---
 
-# Customize built-in policies
+# Customize agent data stream {{ilm-init}} policies
 
 {{es}} includes a set of built-in {{ilm-init}} policies that govern how managed indices transition as they age. This guide demonstrates how you can customize the lifecycle of a managed index, to adjust how the index transitions across [data tiers](/manage-data/lifecycle/data-tiers.md) and what [actions](/manage-data/lifecycle/index-lifecycle-management/index-lifecycle.md#ilm-phase-actions), such as downsampling or shrinking, are performed on the index during each lifecycle phase.