When CsWinRT fails during DesignTimeBuild, the project is skipped as it won't have any outputs.

[jlaanstra]

Describe the bug
When CsWinRT fails during DesignTimeBuild, the project is skipped as it won't have any outputs.

To Reproduce
Reference a WinMD with public types from another WinMD that is not referenced.

Expected behavior
CsWinRT fails to generate the projection but it doesn't fail the design time build.

Version Info
1.3.3

[angelazhangmsft]

Closed by #1105.