refactor(vue): remove support for child routes nested inside of tabs (#22919)

BREAKING CHANGE: Support for child routes nested inside of tabs has been removed to better conform to Vue Router's best practices. Additional routes should be written as sibling routes with the parent tab as the path prefix.

packages/vue/src/components/IonTabs.ts

@@ -19,7 +19,7 @@ export const IonTabs = defineComponent({
             'contain': 'layout size style'
         }
       }, [
-        h(IonRouterOutlet, { tabs: true })
+        h(IonRouterOutlet)
       ])
     ];