If GetControllerTypeInternal falls back to creating an instance, it should also release it (#8196)

src/Umbraco.Web/Mvc/ControllerFactoryExtensions.cs

@@ -25,7 +25,10 @@ namespace Umbraco.Web.Mvc
 
             //we have no choice but to instantiate the controller
             var instance = factory.CreateController(requestContext, controllerName);
-            return instance?.GetType();
+            var controllerType = instance?.GetType();
+            factory.ReleaseController(instance);
+
+            return controllerType;
         }
     }
 }

src/Umbraco.Web/Mvc/MasterControllerFactory.cs

@@ -81,7 +81,10 @@ namespace Umbraco.Web.Mvc
 
                 //we have no choice but to instantiate the controller
                 var instance = factory.CreateController(requestContext, controllerName);
-                return instance?.GetType();
+                var controllerType = instance?.GetType();
+                factory.ReleaseController(instance);
+
+                return controllerType;
             }
 
             return GetControllerType(requestContext, controllerName);