Proposed changes for the WebMessageObjects API to be able to inject web objects into the WebView2 content from app. (#4356)

* Proposed changes for the WebMessageObjects API to be able to inject web objects into the WebView2 content from app and new web object type to represent a FileSystemHandle (#4313)

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Co-authored-by: MikeHillberg <18429489+MikeHillberg@users.noreply.github.com>
Co-authored-by: Raymond Chen <oldnewthing@users.noreply.github.com>

Author: 3 people