Fix configuration binding for HTTP client logging data classifications

[Marcus-Kanon]

Summary

Fixes configuration-based registration for extended HTTP client logging when header data classifications are provided from appsettings.json.

The documented configuration shape for RequestHeadersDataClasses and ResponseHeadersDataClasses uses values like "None" and "Unknown", but the configuration path was relying on default binding behavior that does not bind DataClassification correctly in this scenario. This caused startup failures for AddExtendedHttpClientLogging(configurationSection).

This change:

• replaces default binding with an explicit LoggingOptions configurator for configuration-based registration
• parses configured DataClassification values from string representations such as None and Unknown
• adds regression tests for both IHttpClientBuilder and IServiceCollection registration paths

Testing

• dotnet test .\test\Libraries\Microsoft.Extensions.Http.Diagnostics.Tests\Microsoft.Extensions.Http.Diagnostics.Tests.csproj --filter "BindsRequestHeadersDataClasses"

Fixes #7551

[dotnet-comment-bot]

‼️ Found issues ‼️

Project	Coverage Type	Expected	Actual
Microsoft.Extensions.Http.Diagnostics	Line	94	92.37 🔻
Microsoft.Extensions.Http.Diagnostics	Branch	94	93.81 🔻
Microsoft.Extensions.Diagnostics.Testing	Line	99	98.65 🔻
Microsoft.Extensions.Telemetry	Line	93	91.95 🔻
Microsoft.Extensions.AI	Line	89	88.59 🔻
Microsoft.Extensions.AI	Branch	89	88.53 🔻
Microsoft.Extensions.AI.OpenAI	Line	75	62.65 🔻
Microsoft.Extensions.AI.OpenAI	Branch	75	49.63 🔻
Microsoft.Extensions.DataIngestion.MarkItDown	Line	75	4.46 🔻
Microsoft.Extensions.DataIngestion.MarkItDown	Branch	75	0 🔻
Microsoft.Extensions.Diagnostics.ResourceMonitoring	Line	99	96.03 🔻
Microsoft.Extensions.Diagnostics.ResourceMonitoring	Branch	99	94.39 🔻
Microsoft.Extensions.Diagnostics.ResourceMonitoring.Kubernetes	Line	99	97.73 🔻
Microsoft.Extensions.ServiceDiscovery.Dns	Line	75	69.93 🔻
Microsoft.Extensions.ServiceDiscovery.Abstractions	Line	75	42.11 🔻
Microsoft.Extensions.ServiceDiscovery.Abstractions	Branch	75	42.86 🔻
Microsoft.Extensions.ServiceDiscovery	Line	75	67.96 🔻
Microsoft.Extensions.ServiceDiscovery	Branch	75	71.43 🔻
Microsoft.Extensions.ServiceDiscovery.Yarp	Line	75	73.85 🔻
Microsoft.Extensions.ServiceDiscovery.Yarp	Branch	75	70 🔻
Microsoft.Extensions.VectorData.Abstractions	Line	75	37.39 🔻
Microsoft.Extensions.VectorData.Abstractions	Branch	75	22.73 🔻

🎉 Good job! The coverage increased 🎉
Update MinCodeCoverage in the project files.

Project	Expected	Actual
Microsoft.Gen.BuildMetadata	97	100
Microsoft.Gen.MetadataExtractor	57	73
Microsoft.Gen.MetricsReports	67	69
Microsoft.Extensions.AI.Abstractions	82	85
Microsoft.Extensions.AI.Evaluation.NLP	0	78
Microsoft.Extensions.Caching.Hybrid	82	84
Microsoft.Extensions.DataIngestion	75	89
Microsoft.Extensions.DataIngestion.Markdig	75	90
Microsoft.Extensions.Http.Resilience	97	100

Full code coverage report: https://dev.azure.com/dnceng-public/public/_build/results?buildId=1456079&view=codecoverage-tab