Add Redis cluster mode support to RedisHook

[FrankYang0529]

Why

• Redis Cluster spreads the keyspace over 16384 hash slots and expects the client to route each command to the node owning that slot. A standalone client does not do this — the node replies MOVED and the command fails.

How

• Add a cluster connection extra. When set, get_conn() builds a redis.cluster.RedisCluster, which follows MOVED/ASK redirects.
• Add a startup_nodes extra to supply extra bootstrap nodes.

Verification

• uv run --project providers/redis pytest providers/redis/tests/unit/redis/hooks/test_redis.py -xvs
• breeze testing providers-integration-tests --db-reset --integration redis

• closes: Add support for Redis in Cluster Mode #10504

---

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

• Yes - Claude Code

---

• Read the Pull Request Guidelines for more information. Note: commit author/co-author name and email in commits become permanently public when merged.
• For fundamental code changes, an Airflow Improvement Proposal (AIP) is needed.
• When adding dependency, check compliance with the ASF 3rd Party License Policy.
• For significant user-facing changes create newsfragment: {pr_number}.significant.rst, in airflow-core/newsfragments. You can add this file in a follow-up commit after the PR is created so you know the PR number.