Update UnbrandedGeneratorVersion to 1.0.0-alpha.20250630.1 (#50960)

Co-authored-by: Ubuntu <cloudtest@f32f4fabc00000I.tkkhlgj2u51eln3mcb0lygmbye.dx.internal.cloudapp.net>

Author: azure-sdk

eng/Packages.Data.props

@@ -450,7 +450,7 @@
 
   <PropertyGroup>
     <TestProxyVersion>1.0.0-dev.20250501.1</TestProxyVersion>
-    <UnbrandedGeneratorVersion>1.0.0-alpha.20250627.2</UnbrandedGeneratorVersion>
+    <UnbrandedGeneratorVersion>1.0.0-alpha.20250630.1</UnbrandedGeneratorVersion>
     <AzureGeneratorVersion>1.0.0-alpha.20250629.1</AzureGeneratorVersion>
   </PropertyGroup>
 </Project>