Fix DAG.cli() crashing on dags pause and unpause (#72109)

* Fix DAG.cli() crashing on dags pause and unpause

A Dag file run as a script goes through DAG.cli(), whose parser drops
--dag-id and instead dispatches every subcommand with the Dag object as
a second positional argument. The pause and unpause handlers never
accepted it, so Dag authors got a TypeError instead of the command.

The handlers are only reachable this way from a Dag file, which is why
the regular `airflow dags pause` path has always worked and no test
covered the difference.

* Ignore --treat-dag-id-as-regex when DAG.cli() supplies the Dag

The Dag-scoped parser drops --dag-id but keeps --treat-dag-id-as-regex,
so the flag survives into a context where the user has no pattern left
to supply. The Dag's own id was then read back as a pattern, and dag_ids
may contain dots, so an unanchored match could pause unrelated Dags.

Normalising the flag next to the dag_id it guards covers both of its
readers, including the confirmation prompt, rather than guarding each
reader in turn and leaving the next one to be found later.

* Update airflow-core/tests/unit/cli/commands/test_dag_command.py

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Co-authored-by: Eason09053360 <185830721+Eason09053360@users.noreply.github.com>
Co-authored-by: Henry Chen <henryhenry0512@gmail.com>