fix: support omit name props

[sunecosuri]

If you want to use props in the default layout, you need to specify 'default' for the key named name.

# pages/index.vue
export default defineComponent({
  layout: {
    name: 'default',
    props: { title: 'sample text' },
  }
})

I think it is redundant to write default every time. What do you think of my suggestion?
thank you.