messageDialog: move yes to the right, no to the left.

According to the Google Android guidelines, "The dismissive action
of a dialog is always on the left."
source:
https://uxplanet.org/primary-secondary-action-buttons-c16df9b36150

electrum/gui/qml/components/MessageDialog.qml

@@ -50,15 +50,6 @@ ElDialog {
                 onClicked: doAccept()
             }
 
-            FlatButton {
-                Layout.fillWidth: true
-                Layout.preferredWidth: 1
-                textUnderIcon: false
-                text: qsTr('Yes')
-                icon.source: Qt.resolvedUrl('../../icons/confirmed.png')
-                visible: yesno
-                onClicked: doAccept()
-            }
             FlatButton {
                 Layout.fillWidth: true
                 Layout.preferredWidth: 1
@@ -68,6 +59,15 @@ ElDialog {
                 visible: yesno
                 onClicked: doReject()
             }
+            FlatButton {
+                Layout.fillWidth: true
+                Layout.preferredWidth: 1
+                textUnderIcon: false
+                text: qsTr('Yes')
+                icon.source: Qt.resolvedUrl('../../icons/confirmed.png')
+                visible: yesno
+                onClicked: doAccept()
+            }
         }
     }
 }