Observability: uber [Se] task

[lmolkova]

GA tracing for HTTP and HTTP-based SDKs:

GA blockers (#30557):

• clean up old attributes in azure-core and amqp libs and mappings
• Merge azure-core-tracing-opentelemetry and azure-core-metrics-opentelemetry into a new plugin #41436
• OTel tracing: add option to provide lib-specific schema URL #41485

Can be done post-GA:

• Metrics: investigate how to do HTTP metrics #37442
• Should azure core add InstrumentationPolicy by default whenever azure core httpclient is used #41100
• OTel metrics: support specifying histogram boundaries #41472

Messaging:

• Messaging tracing and metrics: adopt OTel semconv 1.28.0+ #37445
• Documentation and TSG changes for AMQP metrics #30562
• [FEATURE REQ] Observability gaps in EventHubs SDK #38351

GenAI:

• Improve OpenAI tracing and implement metrics #37446
• Improve Azure AI Inference tracing and implement metrics #41893