Change OpenTelemetryChatClient/EmbeddingGenerator to log raw additional properties

[stephentoub]

For historical reasons (based on older versions of the genai convention), we were mangling the key names. Now just use the key names as sourced from the dictionary, enabling a developer to more easily augment the spans with data of their choice.

#6771

Microsoft Reviewers: Open in CodeFlow

[Copilot]

Pull Request Overview

This PR simplifies OpenTelemetry logging by removing key name mangling and using raw property names from additional properties dictionaries. Previously, the code was transforming key names using snake_case conversion and provider-specific prefixes, but now it logs additional properties with their original key names.

• Removed provider-specific tag prefixes and snake_case conversion for additional properties
• Updated test assertions to expect raw key names instead of mangled ones
• Cleaned up unused helper methods and imports

Reviewed Changes

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

Show a summary per file

File	Description
OpenTelemetryChatClient.cs	Simplified additional properties logging to use raw key names
OpenTelemetryEmbeddingGenerator.cs	Simplified additional properties logging to use raw key names
OpenTelemetryConsts.cs	Removed unused PerProvider helper methods
OpenTelemetryChatClientTests.cs	Updated test assertions for new raw key format
OpenTelemetryEmbeddingGeneratorTests.cs	Updated test assertions for new raw key format

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[jeffhandley]

Could someone consider this to be a breaking change if they were doing post-processing on the keys or otherwise relying on the key names in the old structure?

[stephentoub]

Could someone consider this to be a breaking change if they were doing post-processing on the keys or otherwise relying on the key names in the old structure?

Yes, but a) these pale in comparison to the changes made for the 1.37 update, and b) the whole impl is under an Experimental otel namespace because the spec is still changing.