Remove the original package details page (#8977)

This removes the original package details page that was redesigned. There are no functional changes in this PR.

Addresses #8975

Author: loic-sharma

src/AccountDeleter/EmptyFeatureFlagService.cs

@@ -76,16 +76,6 @@ public bool IsDisplayNuGetPackageExplorerLinkEnabled()
             throw new NotImplementedException();
         }
 
-        public bool IsDisplayPackagePageV2Enabled(User user)
-        {
-            throw new NotImplementedException();
-        }
-
-        public bool IsDisplayPackagePageV2PreviewEnabled(User user)
-        {
-            throw new NotImplementedException();
-        }
-
         public bool IsDisplayTargetFrameworkEnabled(User user)
         {
             throw new NotImplementedException();