Remove .py files from being signed (#13005)

* Remove .py files from being signed

Our python starter template has an Authenitcode signature block in its .py files. These aren't wanted because users are meant to change these templates.

Fix #13004

* PR feedback

Author: eerhardt

eng/Signing.props

@@ -8,6 +8,9 @@
 
     <!-- add missing entry for .msi, this can be removed once aspire uses arcade 10.0 -->
     <FileExtensionSignInfo Include=".msi" CertificateName="MicrosoftDotNet500" Condition="!@(FileExtensionSignInfo->AnyHaveMetadataValue('Identity', '.msi'))" />
+
+    <!-- Remove .py files from being signed. See https://github.com/dotnet/aspire/issues/13004 -->
+    <FileExtensionSignInfo Remove=".py" />
   </ItemGroup>
 
   <ItemGroup>