This re-uses the game capture code for checking whether the original
window still exists or not. If it doesn't or the name changed, it'll
insert the value at the top of the list so it doesn't automatically
select another when the user opens properties.
Basically, this fixes an issue where opening properties could sometimes
cause it to instantly capture whatever window was at the top of the
list, which is undesirable.
Closesobsproject/obs-studio#2421