refact: unnecessary es6 feat rm

Author: adamberecz

src/composables/useKeyboard.js

@@ -184,7 +184,7 @@ export default function useKeyboard (props, context, dep)
         break
 
       case 'ArrowLeft':
-        if ((searchable.value && tags.value.querySelector('input').selectionStart) || e.shiftKey || mode.value !== 'tags' || !iv.value?.length) {
+        if ((searchable.value && tags.value.querySelector('input').selectionStart) || e.shiftKey || mode.value !== 'tags' || !iv.value || !iv.value.length) {
           return
         }
 
@@ -199,7 +199,7 @@ export default function useKeyboard (props, context, dep)
         break
 
       case 'ArrowRight':
-        if (activeIndex === -1 || e.shiftKey || mode.value !== 'tags' || !iv.value?.length) {
+        if (activeIndex === -1 || e.shiftKey || mode.value !== 'tags' || !iv.value || !iv.value.length) {
           return
         }