Azure Functions perf degradation since enabling RequestTrackingTelemetryModule and W3C

[lmolkova]

See Azure/azure-functions-host#4551

In https://github.com/Azure/azure-functions-host/releases/tag/v2.0.12408 Azure Functions were configured to use RequestTrackingTelemetryModule from ASP.NET Core SDK and W3C was enabled.

Customer confirmed that disabling RequestTrackingTelemteryModule help to mitigate perf impact: Azure/azure-functions-durable-extension#779 (comment)

To solve it

1. We already have upcoming perf improvements for ASP .NET Cure SDK
2. We need to remove W3C implementation from ApplicationInsighs and leverage one in .NET
3. We need to work with Functions team and measure perf after 1 and 2 are completed.

[lmolkova]

should be fixed with #958 (once finished and shipped)