Update source-build prebuilt baseline (#4503)

Author: MichaelSimons

CODEOWNERS

@@ -9,6 +9,8 @@ PublicAPI.Unshipped.txt @nohwnd @MarcoRossignoli
 TelemetryDataConstants.cs @cvpoienaru @nohwnd
 
 # Changes here might break our contracts with other adapters, and possibly
-# Visual Studio. 
-/src/Microsoft.TestPlatform.AdapterUtilities/ @haplois @Evangelink 
-/test/Microsoft.TestPlatform.AdapterUtilities.UnitTests/  @haplois @Evangelink
+# Visual Studio.
+/src/Microsoft.TestPlatform.AdapterUtilities/ @haplois @Evangelink
+/test/Microsoft.TestPlatform.AdapterUtilities.UnitTests/  @haplois @Evangelink
+
+/src/eng/SourceBuild* @dotnet/source-build-internal

eng/SourceBuild.props

@@ -1,3 +1,5 @@
+<!-- Whenever altering this or other Source Build files, please include @dotnet/source-build-internal as a reviewer. -->
+
 <Project>
 
   <PropertyGroup>

eng/SourceBuildPrebuiltBaseline.xml

@@ -1,7 +1,8 @@
+<!-- Whenever altering this or other Source Build files, please include @dotnet/source-build-internal as a reviewer. -->
+<!-- See aka.ms/dotnet/prebuilts for guidance on what pre-builts are and how to eliminate them. -->
+
 <UsageData>
   <IgnorePatterns>
     <UsagePattern IdentityGlob="Microsoft.SourceBuild.Intermediate.*/*" />
-    <UsagePattern IdentityGlob="Microsoft.Extensions.DependencyModel/3.0.0" />
-    <UsagePattern IdentityGlob="System.Text.Json/4.6.0" />
   </IgnorePatterns>
 </UsageData>