fix: compilation error fixed.

Author: stan-osipov

Editor/UIToolkit/Controls/TabController.cs

@@ -87,6 +87,11 @@ public void ContentContainerFlexGrow(StyleFloat styleFloat)
             m_TabsContainer.contentContainer.style.flexGrow = styleFloat;
         }
 
+        /// <summary>
+        /// Container flex grow property.
+        /// </summary>
+        public StyleFloat ContainerFlexGrow => m_TabsContainer.contentContainer.style.flexGrow;
+
         /// <summary>
         /// Refresh current tab
         /// </summary>

Editor/UIToolkit/PreferencesWindow.meta

@@ -24,11 +24,14 @@ public abstract class PackageSettingsWindow<TWindow> : EditorWindow where TWindo
         /// <summary>
         /// Set/Get the flexible growth property of tabs content container
         /// </summary>
+        
+        
         public StyleFloat ContentFlexGrow
         {
-            get => m_TabsContainer.contentContainer.style.flexGrow;
-            set => m_TabsContainer.contentContainer.style.flexGrow = value;
+            get => m_TabController.ContainerFlexGrow;
+            set => m_TabController.ContentContainerFlexGrow(value);
         }
+        
 
         void OnEnable()
         {