feat(adk): modify cancel func

[meguminnnnnnnnn]

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[codecov]

Codecov Report

❌ Patch coverage is 44.44444% with 5 lines in your changes missing coverage. Please review.
⚠️ Please upload report for BASE (feat/agent_turn_loop@3f17bce). Learn more about missing BASE report.

Files with missing lines	Patch %	Lines
adk/turn_loop.go	42.85%	3 Missing and 1 partial ⚠️
adk/flow.go	0.00%	1 Missing ⚠️

Additional details and impacted files

@@                   Coverage Diff                   @@
##             feat/agent_turn_loop     #800   +/-   ##
=======================================================
  Coverage                        ?   79.55%           
=======================================================
  Files                           ?      148           
  Lines                           ?    16373           
  Branches                        ?        0           
=======================================================
  Hits                            ?    13026           
  Misses                          ?     2378           
  Partials                        ?      969           

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