qml: WCHaveMasterKey: (fix) re-verify text in onTextChanged

fixes https://github.com/spesmilo/electrum/issues/8853

This is a bit ugly, but activeFocus is declared as final and cannot be overridden directly...
```
  1.42 | W | gui.qml.qeapp | file:///home/user/wspace/electrum/electrum/gui/qml/components/controls/ElTextArea.qml:23:5: Cannot override FINAL property
```

electrum/gui/qml/components/controls/ElTextArea.qml

@@ -19,6 +19,7 @@ Flickable {
     property alias inputMethodHints: edit.inputMethodHints
     property alias placeholderText: edit.placeholderText
     property alias color: edit.color
+    readonly property bool anyActiveFocus: activeFocus || edit.activeFocus
 
     contentWidth: rootpane.width
     contentHeight: rootpane.height

electrum/gui/qml/components/wizard/WCHaveMasterKey.qml

@@ -129,8 +129,9 @@ WizardComponent {
                 font.family: FixedFont
                 wrapMode: TextEdit.WrapAnywhere
                 onTextChanged: {
-                    if (activeFocus)
+                    if (anyActiveFocus) {
                         verifyMasterKey(text)
+                    }
                 }
                 inputMethodHints: Qt.ImhSensitiveData | Qt.ImhNoPredictiveText | Qt.ImhNoAutoUppercase
                 background: PaneInsetBackground {