Create HttpClientTransportOptions and utilize it in Confidential Ledger

[christothes]

This PR focuses on the following changes:

• Create HttpPipelineTransportOptions
  • ServerCertificateCustomValidationCallback property allows configuration of a Func<ServerCertificateCustomValidationArgs, bool> delegate to be called when validating the server side TLS certificate
• Create new static overload for HttpPipelineBuilder.Build taking an HttpPipelineTransportOptions to construct the transport with an http handler with all existing defaults and apply the options to the created http handler.
• Automate the setup of the Confidential Ledger client to trust the TLS cert root advertised by the Identity endpoint using the new options

The transport options are applied in the pipeline builder so that we can avoid mutating the provided ClientOptions, which avoids using options with client instance specific transport options on other clients.

In addition, internal to HttpPipelineBuilder, we check if the default Transport has been set after default construction before applying the new transport with transport options applied. In the case that transport options were provided but not applied, an event is logged (PipelineTransportOptionsNotApplied).

[azure-sdk]

API changes have been detected in Azure.Core. You can review API changes here

[azure-sdk]

API changes have been detected in Azure.Core. You can review API changes here

[azure-sdk]

API changes have been detected in Azure.Core. You can review API changes here