extend otel metrics implementation to support provider metrics for register/refresh

[havetisyan]

Description

previously we were using the requestDomainName as the dimension for the provider metrics even though the value was the provider service name. Now, the server has the capability to identify the type of the timer metrics e.g. this is provider latency and in that case, we're using providerServiceName as the label name correctly identifying the attribute.

Contribution Checklist:

• The pull request does not introduce any breaking changes
• I have read the contribution guidelines.
• Create an issue and link to the pull request.

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[gemini-code-assist]

Summary of Changes

Hello @havetisyan, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request significantly improves the accuracy and specificity of OpenTelemetry metrics by introducing a mechanism to differentiate between various types of timed operations. Previously, provider-related latencies were mislabeled; this change ensures that provider service names are correctly attributed to provider latency metrics. This enhancement provides clearer insights into the performance characteristics of different system components, particularly for provider interactions, leading to more effective monitoring and troubleshooting.

Highlights

• Metric Type Differentiation: Introduced a TimerMetricType enum (API_LATENCY, PROVIDER_LATENCY, CERTSIGNER_LATENCY) to categorize different types of timed operations within the Metric interface.
• Provider Metric Labeling: Enhanced the OpenTelemetryMetric implementation to correctly use providerServiceName as a label for PROVIDER_LATENCY metrics, addressing a previous issue where requestDomainName was incorrectly used.
• New startTiming Overload: Added a new startTiming method to the Metric interface and its OpenTelemetryMetric implementation, allowing callers to specify the TimerMetricType.
• ZTS Service Integration: Updated the ZTS service's instance registration and refresh flows to leverage the new provider-specific timing metric, ensuring accurate latency tracking for these operations.

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[gemini-code-assist]

Code Review

This pull request effectively extends the OpenTelemetry metrics implementation to support provider-specific metrics for registration and refresh operations. The introduction of TimerMetricType is a good way to differentiate metric types, and the changes in OpenTelemetryMetric correctly handle PROVIDER_LATENCY by using providerServiceName as a label. The test cases have also been updated accordingly. I've identified a couple of high-severity issues where an incorrect status code is reported in metrics during exception handling, which could lead to misleading monitoring data. I've also suggested a minor refactoring to improve code clarity and maintainability.