Fix: TypingTimer was not stopping for streamingresponses

[tracyboehrer]

Fixes #318

[Copilot]

Pull Request Overview

This PR fixes an issue where the TypingTimer was not stopping during streaming responses. Key changes include:

• Updating the conditional check to handle activities of type Typing when a streaming entity is present.
• Ensuring that the timer properly stops for streaming responses.

Comments suppressed due to low confidence (1)

src/libraries/Builder/Microsoft.Agents.Builder/App/TypingTimer.cs:146

• Consider adding an inline comment to explain that checking 'activity.GetStreamingEntity() != null' supports stopping the timer for streaming responses.

if (activity.Type == ActivityTypes.Message || (activity.Type == ActivityTypes.Typing && activity.GetStreamingEntity() != null))