[#384] Reorganize exports by named exports - agents-hosting and agents-copilotstudio-client

[ceciliaavila]

Addresses #384

Description

This PR removes from the public API classes and methods that should be private because they are intended for internal use.

NOTE:
This PR introduces breaking changes, as previously public members are now inaccessible.

Detailed Changes

• agents-copilotstudio-client
  • Removed the re-export of ExecuteTurnRequest class as it is a wrapper used internally to send the activity in the request's body.
  • Prevented the export of the getCopilotStudioConnectionUrl and getTokenAudience methods as they are used internally to connect with the Copilot Studio agent.
• agents-hosting
  • Avoided exporting the appRoute and RouteList classes as they are internal.
  • Prevented the export of TranscriptLoggerMiddleware by selectively exporting members from transcript.ts.
  • Prevented the export of HeaderPropagation by selectively exporting members from headerPropagation.ts.
  • Prevented the export of CachedAgentState by selectively exporting members from agentState.ts.
  • Removed unused AgentCallbackHandlerKey constant from turnContext.
  • Removed the export of ClaimsIdentity class and Claim interface as they weren't used.
• Updated API docs to reflect the changes.

Testing

These images show the copilotstudio-client samples working (webchat and console).

And these are some samples using the updated hosting features.

[benbrown]

These can be in a list

[ceciliaavila]

Feedback applied. Thanks!