Upload Redis logs in CI

[uglide]

Note

Low Risk
CI-only change with no impact on application runtime or test logic.

Overview
CI debugging: The composite run-tests action now uploads Redis container diagnostics after the test step, using if: always() so logs are captured even when tests fail.

Artifacts are named per matrix inputs (redis-version or client-libs-test-image-tag, plus dotnet-version) and include redis.log and cluster nodes.conf under tests/dockers/cluster/node-* and tests/dockers/standalone/node-*, with if-no-files-found: warn when paths are missing.

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