Add PRI generation support for C++ libraries (#1442)

* Add PRI gen support for libraries.

* Fix mistake. After fix, verified correct.

* Address feedback. Remove unnecessary .NET line. It's not true that TPI is UAP for .NET version less than 5.0. Yes, we require .NET 5 or greater for WAS, but there is no need to have a check here.

* Modified change per feedback.

Author: rohanp-msft

dev/MRTCore/packaging/MrtCore.PriGen.targets

@@ -1,18 +1,10 @@
 <?xml version="1.0" encoding="utf-8" ?>
 <Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003" ToolsVersion="15.0">
 
-  <!-- With .NET 5 and above, the propery TargetPlatformIdentifier is not UAP but rather Windows.
-       Likewise, for other console apps, TargetPlatformIdentifier is Windows.
-       PRI generation in VS apps was developed for UWPs originally. Some of the binaries involved assume
+  <!-- PRI generation in VS apps was developed for UWPs originally. Some of the binaries involved assume
        that the app is a UWP. Change the value provided to said binaries to UAP. -->
   <PropertyGroup>
-    <TargetPlatformIdentifierAdjusted>$(TargetPlatformIdentifier)</TargetPlatformIdentifierAdjusted>
-
-    <!-- Any .NET 5 or greater version is valid here! -->
-    <TargetPlatformIdentifierAdjusted Condition="'$(TargetFrameworkIdentifier)' == '.NETCoreApp' and $([MSBuild]::VersionGreaterThanOrEquals($(TargetFrameworkVersion), '5.0'))">UAP</TargetPlatformIdentifierAdjusted>
-
-    <!-- Add support for console apps. -->
-    <TargetPlatformIdentifierAdjusted Condition="'$(OutputType)' == 'Exe'">UAP</TargetPlatformIdentifierAdjusted>
+    <TargetPlatformIdentifierAdjusted>UAP</TargetPlatformIdentifierAdjusted>
   </PropertyGroup>
 
   <!-- The win32 project system adds all images in the project to the Image array in the project file.