Fix deferrable autofix inserting a forbidden conf import in providers

[FrankYang0529]

Why

• check-deferrable-default rewrites operator and sensor files in place and adds from airflow.configuration import conf. check-conf-import-in-providers forbids that import in provider code, so the two hooks contradict each other.

How

• Change check-deferrable-default to from airflow.providers.common.compat.sdk to conf.

Verification

• uv run --project scripts pytest scripts/tests/ci/prek/test_check_deferrable_default.py

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

• Yes - Claude Code

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