chore: Fix duplication between lastItem() and layoutItem()

Both meant the same thing. Removed the latter.

src/core/Position.cpp

@@ -67,7 +67,7 @@ void Position::addPlaceholderItem(Core::Item *placeholder)
     // meaningful names in separated variables
 }
 
-Core::Item *Position::layoutItem() const
+Core::Item *Position::lastItem() const
 {
     // Return the layout item that is in a MainWindow, that's where we restore the dock widget to.
     // In the future we might want to restore it to FloatingWindows.
@@ -215,6 +215,11 @@ LayoutSaver::Position Position::serialize() const
     return l;
 }
 
+bool Position::isValid() const
+{
+    return lastItem() != nullptr;
+}
+
 Position::ItemRef::ItemRef(KDBindings::ConnectionHandle conn, Core::Item *it)
     : item(it)
     , connection(std::move(conn))

src/core/Position_p.h

@@ -62,19 +62,7 @@ class DOCKS_EXPORT_FOR_UNIT_TESTS Position
      * @brief Returns whether the Position is valid. If invalid then the DockWidget was never
      * in a MainWindow.
      */
-    bool isValid() const
-    {
-        return layoutItem() != nullptr;
-    }
-
-    /**
-     * @brief returns if the dock widget was in a tab
-     * @return if the position is tabbed, false otherwise
-     */
-    bool isTabbed() const
-    {
-        return m_tabIndex != -1;
-    }
+    bool isValid() const;
 
     ///@brief The tab index in case the dock widget was in a TabWidget, -1 otherwise.
     int m_tabIndex = -1;
@@ -85,8 +73,6 @@ class DOCKS_EXPORT_FOR_UNIT_TESTS Position
     ///@brief Adds the last layout item where the dock widget was (or is)
     void addPlaceholderItem(Core::Item *placeholder);
 
-    Core::Item *layoutItem() const;
-
     bool containsPlaceholder(Core::Item *) const;
     void removePlaceholders();
 
@@ -120,10 +106,7 @@ class DOCKS_EXPORT_FOR_UNIT_TESTS Position
         return m_lastFloatingGeometry;
     }
 
-    Core::Item *lastItem() const
-    {
-        return layoutItem();
-    }
+    Core::Item *lastItem() const;
 
     int lastTabIndex() const
     {