Fixed issue where adaptive card inputs were being reset.

[tonyanziano]

Fixes #1680

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The root cause is that when an activity is clicked on, it fires off both highlight activity & set inspector objects actions that then modify the chat document in the store.

This change in the store causes the chat.tsx component to re-render and the entire Web Chat control with it, which wipes the state of input fields within adaptive cards.

Preventing that re-render from happening seems like a very hard problem, if not impossible, given our current DOM structure.

The fix here is to intercept clicks & keydown events within activities, check if they originated within an input field, and prevent the highlight and select activity actions from being fired.