Revert "Fixed issue with saving content when having an empty variant.…

… Aligned codebase with how it is in v8"

This reverts commit 5ae0b64.

src/Umbraco.Web.BackOffice/Controllers/ContentController.cs

@@ -913,9 +913,14 @@ private async Task<ActionResult<ContentItemDisplay>> PostSaveInternal(ContentIte
                     v.Notifications.AddRange(n.Notifications);
             }
 
-            //lastly, if it is not valid, add the model state to the outgoing object and throw a 400
             HandleInvalidModelState(display, cultureForInvariantErrors);
 
+            //lastly, if it is not valid, add the model state to the outgoing object and throw a 400
+            if (!ModelState.IsValid)
+            {
+                return ValidationProblem(display, ModelState);
+            }
+
             if (wasCancelled)
             {
                 AddCancelMessage(display);