Fixing event pipeline provider type

[MichaelGHSeg]

Custom pipelines can now be set, plus a test to validate they are used.

[Copilot]

PR Overview

This PR updates the event pipeline provider configuration to use a custom provider interface and validates its usage through new tests.

• Updates Configuration.cs to accept IEventPipelineProvider instead of a concrete type.
• Introduces new tests validating both standard and custom event pipeline provider implementations.

Reviewed Changes

File	Description
Tests/Utilities/EventPipelineTest.cs	Adds tests to validate that the event pipeline providers, both standard and custom, are used in the configuration.
Analytics-CSharp/Segment/Analytics/Configuration.cs	Changes the parameter type for event pipeline provider to IEventPipelineProvider, supporting pluggable custom implementations.

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

Comments suppressed due to low confidence (2)

Tests/Utilities/EventPipelineTest.cs:225

• [nitpick] Consider adding an assertion to verify that the event pipeline provider is actively processing or modifying events, to ensure complete test coverage of the provider integration.

analytics.Track("test");

Tests/Utilities/EventPipelineTest.cs:241

• [nitpick] Consider asserting the exception message or adding further validation to ensure that the NotImplementedException is raised for the expected reason, if a specific message is available.

Assert.Throws<NotImplementedException>(() => {