Reflecting how runtime is selected in the host app WebView2 instance details pane

[victorhuangwq]

Display in the WebView2 instance details pane about which overrides are active, and if both are active, state that the reg key is overriding.

Addresses #72, #73

[david-risney]

Maybe merge somehow the Open Override button with the which overrides are applying.

[david-risney]

This is dup of other issue.