Change step back shortcut in command palette to Shift+Backspace (#5604)

* Change cmdbar step back shortcut to Shift+Backspace

* Add visual button for step back

* Make the shortcut apply no matter what's in the input

src/components/CommandBar/CommandBarSelectionMixedInput.tsx

@@ -120,7 +120,7 @@ export default function CommandBarSelectionMixedInput({
           placeholder="Select an entity with your mouse"
           className="absolute inset-0 w-full h-full opacity-0 cursor-default"
           onKeyDown={(event) => {
-            if (event.key === 'Backspace') {
+            if (event.key === 'Backspace' && event.shiftKey) {
               stepBack()
             } else if (event.key === 'Escape') {
               commandBarActor.send({ type: 'Close' })