Make menu left arrow navigate back

shell/plugins/menu/Menu.qml

@@ -840,7 +840,7 @@ Item {
           } else if (Util.editsFilter(event, root.filterText)) {
             root.setFilter(Util.editedFilter(event, root.filterText))
             event.accepted = true
-          } else if (event.key === Qt.Key_Backspace && !root.filterText) {
+          } else if ((event.key === Qt.Key_Backspace || event.key === Qt.Key_Left) && !root.filterText) {
             root.goBack()
             event.accepted = true
           } else if (event.key === Qt.Key_Up) {

test/shell.d/menu-test.sh

@@ -118,6 +118,10 @@ assert(
   /function setActiveMenu\(id, pushHistory\)[\s\S]*root\.disarmPointer\(\)/.test(menuQml),
   'menu route changes disarm pointer selection'
 )
+assert(
+  /\(event\.key === Qt\.Key_Backspace \|\| event\.key === Qt\.Key_Left\) && !root\.filterText[\s\S]*root\.goBack\(\)/.test(menuQml),
+  'menu Left key follows empty-filter Backspace navigation'
+)
 assert(
   /PointerMoveGate\s*\{[\s\S]*id: pointerGate[\s\S]*referenceItem: card[\s\S]*\}/.test(menuQml),
   'menu uses shared pointer movement gate in card coordinates'