Merged PR 21931: Revert "[release/6.0] Build ProjectTemplates in Source-Build (#40650)" (#40805)

# {PR title}

Summary of the changes (Less than 80 chars)

## Description

{Detail}

Fixes #{bug number} (in this specific format)

## Customer Impact

{Justification}

## Regression?

- [ ] Yes
- [ ] No

[If yes, specify the version the behavior has regressed from]

## Risk

- [ ] High
- [ ] Medium
- [ ] Low

[Justify the selection above]

## Verification

- [ ] Manual (required)
- [ ] Automated

## Packaging changes reviewed?

- [ ] Yes
- [ ] No
- [ ] N/A

----

## When servicing release/2.1

- [ ] Make necessary changes in eng/PatchConfig.props

Revert "[release/6.0] Build ProjectTemplates in Source-Build (#40650)" (#40805)

This reverts commit 7c2000d3.

Directory.Build.props

@@ -30,9 +30,6 @@
           $(MSBuildProjectName.EndsWith('.Test')) OR
           $(MSBuildProjectName.EndsWith('.FunctionalTest')) ) ">true</IsUnitTestProject>
     <IsTestAssetProject Condition=" $(RepoRelativeProjectDir.Contains('testassets')) OR $(MSBuildProjectName.Contains('TestCommon'))">true</IsTestAssetProject>
-    <IsProjectTemplateProject Condition=" ($(RepoRelativeProjectDir.Contains('ProjectTemplates')) OR $(MSBuildProjectName.Contains('ProjectTemplates')) ) AND
-        '$(IsUnitTestProject)' != 'true' AND
-        '$(IsTestAssetProject)' != 'true' ">true</IsProjectTemplateProject>
     <IsSampleProject Condition=" $(RepoRelativeProjectDir.ToUpperInvariant().Contains('SAMPLE')) ">true</IsSampleProject>
     <IsAnalyzersProject Condition="$(MSBuildProjectName.EndsWith('.Analyzers'))">true</IsAnalyzersProject>
     <IsShipping Condition=" '$(IsSampleProject)' == 'true' OR

Directory.Build.targets

 <Project>
 
   <PropertyGroup>
-    <!-- Only build Microsoft.AspNetCore.App, Microsoft.AspNetCore.App.Ref, ref/ assemblies, and ProjectTemplates in source build. -->
+    <!-- Only build Microsoft.AspNetCore.App, Microsoft.AspNetCore.App.Ref, and ref/ assemblies in source build. -->
     <!-- Analyzer package are needed in source build for WebSDK -->
     <ExcludeFromSourceBuild
-        Condition="'$(ExcludeFromSourceBuild)' == '' and 
-            '$(DotNetBuildFromSource)' == 'true' and 
-            '$(IsAspNetCoreApp)' != 'true' and 
-            '$(MSBuildProjectName)' != '$(TargetingPackName)' and 
-            '$(IsAnalyzersProject)' != 'true' and 
-            '$(IsProjectTemplateProject)' != 'true'">true</ExcludeFromSourceBuild>
+        Condition="'$(ExcludeFromSourceBuild)' == '' and '$(DotNetBuildFromSource)' == 'true' and '$(IsAspNetCoreApp)' != 'true' and '$(MSBuildProjectName)' != '$(TargetingPackName)' and '$(IsAnalyzersProject)' != 'true'">true</ExcludeFromSourceBuild>
 
     <!-- If the user has specified that they want to skip building any test related projects with SkipTestBuild,
      suppress all targets for TestProjects using ExcludeFromBuild. -->