qml: make ConfirmTxDialog flickable if content larger than window (fixes #8446)

electrum/gui/qml/components/ConfirmTxDialog.qml

@@ -35,14 +35,23 @@ ElDialog {
     }
 
     ColumnLayout {
-        width: parent.width
-        height: parent.height
+        anchors.fill: parent
         spacing: 0
 
-        GridLayout {
+        Flickable {
             Layout.fillWidth: true
-            Layout.leftMargin: constants.paddingLarge
-            Layout.rightMargin: constants.paddingLarge
+            Layout.fillHeight: true
+
+            leftMargin: constants.paddingLarge
+            rightMargin: constants.paddingLarge
+
+            contentHeight: rootLayout.height
+            clip: true
+            interactive: height < contentHeight
+
+            GridLayout {
+                id: rootLayout
+                width: parent.width
 
                 columns: 2
 
@@ -191,8 +200,7 @@ ElDialog {
                     }
                 }
             }
-
-        Item { Layout.fillHeight: true; Layout.preferredWidth: 1 }
+        }
 
         FlatButton {
             id: sendButton