fix(vue-compat): Ensure getDefaultSlots works with @vue/compat & Vue 3 (

#6016)

fix(vue-instantsearch): Ensure getDefaultSlots works with @vue/compat & Vue 3

packages/vue-instantsearch/src/util/vue-compat/index-vue3.js

@@ -49,5 +49,13 @@ export function renderCompat(fn) {
 }
 
 export function getDefaultSlot(component) {
-  return component.$slots.default && component.$slots.default();
+  const $slots = component.$slots || component.slots;
+
+  if (typeof $slots.default === 'function') {
+    // Vue 3
+    return $slots.default();
+  }
+
+  // Vue 3 with @vue/compat
+  return $slots.default;
 }