docs: Fix token exceeded error on ADK release analyzer's final summary agent

Co-authored-by: Xuan Yang <xygoogle@google.com>
PiperOrigin-RevId: 944711030

Author: xuanyang15

contributing/samples/adk_team/adk_documentation/adk_release_analyzer/agent.py

@@ -559,6 +559,7 @@ def summary_instruction(readonly_context: ReadonlyContext) -> str:
     name="summary_agent",
     description="Compiles recommendations and creates the GitHub issue.",
     instruction=summary_instruction,
+    include_contents="none",
     tools=[
         get_all_recommendations,
         create_issue,