Flag deprecated expose_config=non-sensitive-only in config lint

[FrankYang0529]

Why

• [api] expose_config = non-sensitive-only was deprecated in Treat non-sensitive-only as true and always mask sensitive values in public api's #59880 (3.2.0), but the only signal is a DeprecationWarning that the api-server emits once per process while serving GET /config.
• On a config file that still carries non-sensitive-only, airflow config lint and airflowctl config lint report "No issues found in your airflow.cfg. It is ready for Airflow 3!".

How

• Add a value-level ConfigChange rule (was_removed=False, is_invalid_if="non-sensitive-only") to both CONFIGS_CHANGES lists, following the existing rule.

Verification

• Unit test
  • uv run --frozen --project airflow-core pytest airflow-core/tests/unit/cli/commands/test_config_command.py
  • uv run --frozen --project airflow-ctl pytest airflow-ctl/tests/airflow_ctl/ctl/commands/test_config_command.py
• Integration test:

export AIRFLOW_HOME=/tmp/airflow-lint && mkdir -p $AIRFLOW_HOME
.venv/bin/airflow config lint --section api
sed -i '' 's/^expose_config = .*/expose_config = non-sensitive-only/' $AIRFLOW_HOME/airflow.cfg && grep -n '^expose_config' $AIRFLOW_HOME/airflow.cfg
.venv/bin/airflow config lint

On main branch, it shows No issues found in your airflow.cfg. It is ready for Airflow 3!. In this branch, it shows:

Found issues in your airflow.cfg:
  - Invalid value `non-sensitive-only` set for `expose_config` configuration parameter in `api` section. This value is deprecated and treated as
`True`. Set `expose_config` to `True` instead; sensitive configuration values are always masked.

Please update your configuration file accordingly.

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Was generative AI tooling used to co-author this PR?

• Yes - Claude Code

---

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