Default ReportAbuseUriTemplate is hardcoded to nuget.org

[scottbommarito]

As noted in https://github.com/NuGet/NuGet.Services.Index/pull/57, nuget.exe has a fallback for a missing ReportAbuseUriTemplate in index.json to use the value for nuget.org.

This is bad for a number of reasons:
1 - The field will show garbage if the user is using a NuGet server (MyGet, VSTS) that is not nuget.org that has not specified a ReportAbuseUriTemplate.
2 - If the schema ever changes, nuget.exe will continue to use an outdated schema.

I suggest falling back to null like our other URI fields.

[agr]

Related to #1787?

[psfinaki]

Any update on this?