feat: implement custom feedback form

[lilyydu]

Custom Feedback Context:
Learn Doc

• previously we had a flag called feedbackLoopEnabled which only enables the default feedback form
• now, we have a param called feedbackLoop that can either be default or custom.
• updated AI sample to feature the custom feedback loop
• also included the normalization to feedbackLoop when using withChannelData..
• py equivalent: feat/bug: add custom feedback form & fix pydantic valid error on MessageUpdateActivity teams.py#349
• ts equivalent: feat: add custom feedback loop teams.ts#522

[Copilot]

Pull request overview

This PR adds support for Teams “custom feedback” loops by introducing a feedbackLoop channelData configuration (default vs custom), adding a new message/fetchTask invoke activity model + Apps handler registration, and updating the AI sample to demonstrate a custom feedback dialog flow.

Changes:

• Add FeedbackLoop / FeedbackType models and normalize legacy feedbackLoopEnabled into feedbackLoop.
• Add message/fetchTask invoke activity support (API model + Apps routing extension + deserialization support).
• Update Samples.AI to use FeedbackType.Custom and return a task module dialog; add Apps tests for the new handler.

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
Tests/Microsoft.Teams.Apps.Tests/Activities/Invokes/Messages/FetchTaskActivityTests.cs	Adds coverage to ensure OnMessageFetchTask routes and handlers are invoked correctly.
Samples/Samples.AI/Samples.AI.csproj	Adds Cards project reference needed to build adaptive cards for the custom dialog.
Samples/Samples.AI/Program.cs	Registers OnMessageFetchTask handler for custom feedback dialogs.
Samples/Samples.AI/Handlers/FeedbackHandler.cs	Switches sample to FeedbackType.Custom and builds a task module adaptive card for feedback.
Libraries/Microsoft.Teams.Apps/Activities/Invokes/Messages/FetchTaskActivity.cs	Adds attribute + OnMessageFetchTask route registration for message/fetchTask.
Libraries/Microsoft.Teams.Api/FeedbackLoop.cs	Introduces FeedbackType string enum + FeedbackLoop configuration model.
Libraries/Microsoft.Teams.Api/ChannelData.cs	Adds feedbackLoop property and documents legacy feedbackLoopEnabled.
Libraries/Microsoft.Teams.Api/Activities/Invokes/Messages/FetchTaskActivity.cs	Adds the message/fetchTask activity model + reaction payload types.
Libraries/Microsoft.Teams.Api/Activities/Invokes/MessageActivity.cs	Updates message invoke polymorphic (de)serialization to include fetchTask.
Libraries/Microsoft.Teams.Api/Activities/Activity.cs	Normalizes feedback fields during WithData(ChannelData) and adds AddFeedback(FeedbackType) overload.

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[Copilot]

Pull request overview

Copilot reviewed 10 out of 10 changed files in this pull request and generated 2 comments.

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