Refactoring DatabaseCacheRepository to de-duplicate code and remove warnings (#19942)

* Refactoring to de-duplicate code and remove warnings.

* Update src/Umbraco.PublishedCache.HybridCache/Persistence/DatabaseCacheRepository.cs

Co-authored-by: Copilot <[email protected]>

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Co-authored-by: Copilot <[email protected]>

Author: AndyButland