QmlDesigner: Handle text overflow state for ComboBox

- Text is elided in the overflow state.
- Text is aligned to the left in the overflow state.

Task-number: QDS-9402
Change-Id: If1cca917a42b8198729591506e8a886ea9a70814
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>
Reviewed-by: Mahmoud Badri <mahmoud.badri@qt.io>
Reviewed-by: Miikka Heikkinen <miikka.heikkinen@qt.io>

share/qtcreator/qmldesigner/propertyEditorQmlSources/imports/StudioControls/ComboBoxInput.qml

@@ -32,6 +32,20 @@ TextInput {
     selectByMouse: false
     activeFocusOnPress: false
     clip: true
+    echoMode: TextInput.NoEcho
+
+    Text {
+        id: elidableText
+        anchors.fill: control
+        leftPadding: control.leftPadding
+        rightPadding: control.rightPadding
+        horizontalAlignment: control.horizontalAlignment
+        verticalAlignment: control.verticalAlignment
+        font: control.font
+        color: control.color
+        text: control.text
+        elide: Text.ElideRight
+    }
 
     Rectangle {
         id: background
@@ -128,6 +142,14 @@ TextInput {
                 target: background
                 color: control.style.background.interaction
             }
+            PropertyChanges {
+                target: control
+                echoMode: TextInput.Normal
+            }
+            PropertyChanges {
+                target: elidableText
+                visible: false
+            }
             PropertyChanges {
                 target: mouseArea
                 cursorShape: Qt.IBeamCursor