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

[Copilot]

The ClearServiceProviderCache extension method is missing the required internal API XML documentation comment. According to EF Core coding guidelines, all members in Internal namespaces must include the standard internal API documentation comment that warns users about using internal APIs.

[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