Update SkillHandler to use ContinueConversationAsync overload with audience #3451
Description
Describe the bug
SkillHandler needs to provide the correct audience when calling BotFrameworkAdapter.ContinueConversationAsync (#3409). It will get this audience from the SkillConversationIdFactory implementation.
Additional context
Update SkillConversationIdFactoryBase to take and return the correct Audience/OAuthScope #3449
Update SkillHttpClient/BotFrameworkClient to include overload that uses audience #3450
PR #3409 that added ContinueConversationAsync overload to require audience.
[bug]