revert undo shortcut change in browser

when ctrl+z pressed in focused field and no undo history left, qt
triggers the menu item instead, causing data loss

I tried capturing the shortcut in JS and manually executing the undo,
and that seems to work on macOS, but not on Windows.

fixes
https://anki.tenderapp.com/discussions/ankidesktop/33064-how-to-undo-reverted-to-state-deleting-my-cards

aqt/browser.py

@@ -421,8 +421,6 @@ class Browser(QMainWindow):
         f.filter.clicked.connect(self.onFilterButton)
         # edit
         f.actionUndo.triggered.connect(self.mw.onUndo)
-        if qtminor < 11:
-            f.actionUndo.setShortcut(QKeySequence(_("Ctrl+Alt+Z")))
         f.actionInvertSelection.triggered.connect(self.invertSelection)
         f.actionSelectNotes.triggered.connect(self.selectNotes)
         if not isMac:

designer/browser.ui

@@ -339,7 +339,7 @@
     <string>&amp;Undo</string>
    </property>
    <property name="shortcut">
-    <string>Ctrl+Z</string>
+    <string>Ctrl+Alt+Z</string>
    </property>
   </action>
   <action name="actionInvertSelection">