LibGUI: HeaderView should always notify parent when sections resize

The view needs to recompute the scrollable content size whenever this
happens, so let's always notify it. Previously we were only doing this
when resizing columns with interactively (not programmatically.)

Libraries/LibGUI/HeaderView.cpp

@@ -60,8 +60,12 @@ HeaderView::~HeaderView()
 void HeaderView::set_section_size(int section, int size)
 {
     auto& data = section_data(section);
+    if (data.size == size)
+        return;
     data.size = size;
     data.has_initialized_size = true;
+    data.size = size;
+    m_table_view.header_did_change_section_size({}, m_orientation, section, size);
 }
 
 int HeaderView::section_size(int section) const
@@ -146,12 +150,7 @@ void HeaderView::mousemove_event(MouseEvent& event)
         if (new_size <= minimum_column_size)
             new_size = minimum_column_size;
         ASSERT(m_resizing_section >= 0 && m_resizing_section < model()->column_count());
-        auto& data = this->section_data(m_resizing_section);
-        if (data.size != new_size) {
-            data.size = new_size;
-            m_table_view.header_did_change_section_size({}, m_orientation, m_resizing_section, new_size);
-            update();
-        }
+        set_section_size(m_resizing_section, new_size);
         return;
     }