fix(tabs-extended): add vertical arrow key support (#8243)

### Related Ticket(s)

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fixes #7719

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Adds arrow-up and arrow-down navigation to the tabs-extended component

### Changelog

**Changed**

- Adds arrow-up and arrow-down navigation to the tabs-extended component

packages/web-components/src/components/tabs-extended/tabs-extended.ts

@@ -88,6 +88,12 @@ class DDSTabsExtended extends StableSelectorMixin(LitElement) {
           this._setActiveItem(this._getNextTab(activeTab));
         }
         break;
+      case 'ArrowUp':
+        this._setActiveItem(this._getPrevTab(activeTab));
+        break;
+      case 'ArrowDown':
+        this._setActiveItem(this._getNextTab(activeTab));
+        break;
       case 'Home':
         this._setActiveItem(this._getNextTab(-1));
         break;