[exporter/azuremonitor] add configurable HTTP success mapping

[tombiddulph]

Description

The Azure Monitor exporter currently marks any HTTP span with a status code
outside 100–399 as Success = false on the resulting Application Insights
RequestData / RemoteDependencyData

This causes expected 4xx responses (most notably 404 for cache misses,
existence checks, optional resources, etc.) to show up as failed
requests/dependencies in Application Insights dashboards and alerts. It also
diverges from the OpenTelemetry HTTP semantic conventions, which state that
4xx on server spans should not set the span status to Error.

Spec for reference.

This pr adds two opt-in settings to the Azure Monitor exporter:

• non_error_http_status_codes (list of HTTP status codes treated as Success on both server and client HTTP spans) and
• align_http_server_request_success_with_otel_spec (when true, 4xx responses on HTTP server spans are treated as Success, matching the OpenTelemetry HTTP semantic conventions). Defaults preserve the existing exporter behaviour.

Link to tracking issue

Fixes #47691

Testing

-Added a unit test for the existing behaviour and the opt in features

Documentation

• Updated the readme with the new features
• Added to the changelog

Authorship

• I, a human, wrote this pull request description myself.

[github-actions]

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