fix(components): improve generic types (#3331)

Co-authored-by: Benjamin Canac <canacb1@gmail.com>

docs/app/components/content/examples/select/SelectFetchExample.vue

@@ -1,4 +1,6 @@
 <script setup lang="ts">
+import type { AvatarProps } from '@nuxt/ui'
+
 const { data: users, status } = await useFetch('https://jsonplaceholder.typicode.com/users', {
   key: 'typicode-users',
   transform: (data: { id: number, name: string }[]) => {
@@ -6,7 +8,7 @@ const { data: users, status } = await useFetch('https://jsonplaceholder.typicode
       label: user.name,
       value: String(user.id),
       avatar: { src: `https://i.pravatar.cc/120?img=${user.id}` }
-    })) || []
+    }))
   },
   lazy: true
 })
@@ -18,17 +20,18 @@ function getUserAvatar(value: string) {
 
 <template>
   <USelect
-    :items="users || []"
+    :items="users"
     :loading="status === 'pending'"
     icon="i-lucide-user"
     placeholder="Select user"
     class="w-48"
+    value-key="value"
   >
     <template #leading="{ modelValue, ui }">
       <UAvatar
         v-if="modelValue"
-        v-bind="getUserAvatar(modelValue as string)"
-        :size="ui.leadingAvatarSize()"
+        v-bind="getUserAvatar(modelValue)"
+        :size="(ui.leadingAvatarSize() as AvatarProps['size'])"
         :class="ui.leadingAvatar()"
       />
     </template>