[wix-devs] 5355 - util:RegistrySearch clears the variable when the key or value is not found

[Sean Hall]

I'd like to get  https://github.com/wixtoolset/issues/issues/5355 designed
since the proposal is technically a breaking change: "Rather than add a
Default attribute, maybe the search should work like MSI, where a missing
value doesn't overwrite the default." I think the proposal is good, unless
someone else wants to do it differently?