[Sidebar] Use leadingPadding: consistently for list items

sidebar/package/contents/ui/CategoriesPage.qml

@@ -145,7 +145,7 @@ Kirigami.ScrollablePage {
                 return delegate.ListView.view.model.rowCount(modelIndex) > 1
             }
             // Only indent subcategory icons in the search view
-            isSearching: searchField.text.length > 0
+            leadingPadding: (model.DepthRole > 1 && searchField.text.length > 0) ? (( model.DepthRole - 1 ) * Kirigami.Units.iconSizes.smallMedium) + Kirigami.Units.largeSpacing : 0
 
             hoverEnabled: !model.IsCategoryRole || !mainColumn.searchMode
             enabled: model.IsKCMRole || !mainColumn.searchMode

sidebar/package/contents/ui/CategoryItem.qml

@@ -15,10 +15,10 @@ Kirigami.BasicListItem {
     property bool selected: delegate.highlighted || delegate.pressed
     property bool isSearching: false
 
+    // Dummy item to make leadingPadding value manipulable by clients
     leading: Item {
-        width: (model.DepthRole > 1 && delegate.isSearching) ? (( model.DepthRole - 1 ) * Kirigami.Units.iconSizes.smallMedium) + Kirigami.Units.largeSpacing : 0
+        width: 0
     }
-    // We are manipulating the padding in the leading item itself, so set this to 0
     leadingPadding: 0
 
     icon: model.decoration

sidebar/package/contents/ui/SubCategoryPage.qml

@@ -141,6 +141,7 @@ Kirigami.ScrollablePage {
         delegate: CategoryItem {
             id: delegate
 
+            // Indent items that are children of other KCMs within the same group
             leadingPadding: model.DepthRole > 2 ? (( model.DepthRole - 2 ) * Kirigami.Units.iconSizes.smallMedium) + Kirigami.Units.largeSpacing : 0
 
             onClicked: {