Overview: Fix clear button working in overview search

onTextEdited only updates on user-invoked key presses, and not
programatic changes.

This is a better choice when we have a two-way bindings such  as with
configuration files, but in this case we always want the UI to reflect
the current contents of the search box making onTextChanged the better
signal.

BUG: 475789

src/plugins/overview/qml/main.qml

@@ -264,7 +264,8 @@ FocusScope {
             Keys.priority: Keys.BeforeItem
             Keys.forwardTo: text && (allDesktopHeaps.currentHeap.count === 0 || !effect.filterWindows) ? searchResults : allDesktopHeaps.currentHeap
             text: effect.searchText
-            onTextEdited: {
+            // not onTextEdited so that the UI always stays in sync
+            onTextChanged: {
                 effect.searchText = text;
                 allDesktopHeaps.currentHeap.resetSelected();
                 allDesktopHeaps.currentHeap.selectNextItem(WindowHeap.Direction.Down);