Add mechanism to clear ServiceProviderCache (#27189)

[Abde1rahman1]

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Summary

This PR implements a "pubternal" way to clear the internal service provider cache, as requested in #27189. This allows developers to resolve memory leaks and state corruption issues, especially in heavy testing scenarios where many internal service providers are created.

Changes

• Added Clear() to ServiceProviderCache to allow clearing the internal _configurations dictionary.

• Added a static ClearServiceProviderCache() method to EntityFrameworkMetrics in the Infrastructure.Internal namespace.

• Added a unit test in ServiceProviderCacheTest to ensure the cache is effectively cleared.

• Tests for the changes have been added (for bug fixes / features)

• Code follows the same patterns and style as existing code in this repo

[Copilot]

Pull request overview

This PR implements a mechanism to clear the internal EF Core service provider cache to address memory leaks in testing scenarios. The implementation adds a Clear() method to ServiceProviderCache and exposes it through a static method on EntityFrameworkMetrics and an extension method on DatabaseFacade.

Changes:

• Added Clear() method to ServiceProviderCache to clear the internal configurations dictionary
• Added static ClearServiceProviderCache() entry point (intended but incomplete)
• Added DatabaseFacade extension method to provide a public API surface
• Added unit test to verify cache clearing functionality

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 5 comments.

File	Description
src/EFCore/Internal/ServiceProviderCache.cs	Adds virtual Clear() method to clear the internal _configurations dictionary
src/EFCore/Infrastructure/Internal/EntityFrameworkMetrics.cs	Adds using statement for ServiceProviderCache namespace (but missing the actual static method implementation)
src/EFCore/Infrastructure/Internal/InfrastructureExtensions.cs	Adds DatabaseFacade extension method to call EntityFrameworkMetrics.ClearServiceProviderCache()
test/EFCore.Tests/ServiceProviderCacheTest.cs	Adds test that verifies cache clearing using reflection to check internal state

[Abde1rahman1]

@AndriySvyryd , Done. I've addressed all comments: updated the XML documentation with the concurrency warning, removed the redundant extension method as requested, and enhanced the test to verify functional behavior by asserting that a new service provider instance is created after clearing the cache

[AndriySvyryd]

Thanks for your contribution!