Dialog merge results should include iconUrl if present in component

[benbrown]

Is your feature request related to a problem? Please describe.

When using the dialog merge command, the results currently include the PackageIcon field from dotnet components. This value is typically a relative path, not an absolute URL, thus not usable in Composer.

See: microsoft/botframework-components#802

Describe the solution you'd like

Please include the PackageIconUrl field if included in the csproj file. Ideally this would be included as iconUrl in the results.