CircuitBreaker: Partition availability staleness check background thread should be a daemon thread to not block apps from closing gracefully

[FabianMeiswinkel]

Description

The background thread to check partition availability when Circuit breaker is enabled - partition-availability-staleness-check - is not a daemon thread. This results in apps hanging instead of gracefully closing - example is the benchmark console app.

All SDK Contribution checklist:

• The pull request does not introduce [breaking changes]
• CHANGELOG is updated for new features, bug fixes or other significant changes.
• I have read the contribution guidelines.

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• Title of the pull request is clear and informative.
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Testing Guidelines

• Pull request includes test coverage for the included changes.

[kushagraThapar]

looks good, thanks Fabian!

[azure-sdk]

API change check

API changes are not detected in this pull request.