Teams Extension to use Teams SDK models and clients

[tracyboehrer]

• Agents SDK will take ownership of the Teams extension and
  • Use Teams SDK models and clients, removing those from the Teams Extension
  • Support proper serialization of Teams SDK models with conversion to Agents SDK Core equivalent if required.
  • Eliminate TeamsConnectorClient and use the Teams clients in TeamsInfo
  • The Teams client should be available from within an AgentApplication handler (by some means).
• Add missing Teams functionality that Teams SDK supports (where possible)
• This will be a breaking change as method signatures and types change
• Since this will be an Agents SDK owned and supported package, it should conform to our normal stylistic and usage patterns
• Agents SDK will remain in control of ingress/egress. i.e.., Host, Adapter, TurnContext operates as before. We are just handling Teams specific routing and model serialization.
• This should be coupled with a Claude Skill to assist in migration from current Teams Extension to new.