[main] Update dependencies from dotnet/source-build-externals (#69779)

[main] Update dependencies from dotnet/source-build-externals

Author: dotnet-maestro[bot]

eng/Version.Details.xml

@@ -1,9 +1,9 @@
 <?xml version="1.0" encoding="utf-8"?>
 <Dependencies>
   <ProductDependencies>
-    <Dependency Name="Microsoft.SourceBuild.Intermediate.source-build-externals" Version="8.0.0-alpha.1.23429.1">
+    <Dependency Name="Microsoft.SourceBuild.Intermediate.source-build-externals" Version="8.0.0-alpha.1.23456.1">
       <Uri>https://github.com/dotnet/source-build-externals</Uri>
-      <Sha>0603839a51f5e18b89c60a3690aff5e81fa666ca</Sha>
+      <Sha>1b64d3c0fad8af67da8f42927ce7306730224c15</Sha>
       <SourceBuild RepoName="source-build-externals" ManagedOnly="true" />
     </Dependency>
     <Dependency Name="Microsoft.SourceBuild.Intermediate.source-build-reference-packages" Version="8.0.0-alpha.1.23211.4">