related: https://apache-airflow.slack.com/archives/C06K9Q5G2UA/p1769642556328069?thread_ts=1769631389.812549&cid=C06K9Q5G2UA

Improve: #59430

I improve the logic by checking various cases and identifying undetected or incorrectly detected scenarios from the initial version.

• Fixed the issue where sdk.DAG(dag_id='dag_id') was not detected when used instead of DAG(dag_id='dag_id') .
• Modified to skip checking functions defined with @task that are serialized by plain code.
• Previously checked all functions defined within with DAG blocks, but now modified to only check functions whose names end with Operatoror Task.
• Even if a warning occurs in a function definition, the warning is not exposed if the function is not actually called.

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