chore(vue3): always pass an object as slot scope and listeners

What does this MR do?

Vue3 blows up if you pass undefined as slot-scope and @vue/compat complains if you pass undefined to v-on Pass empty objects instead

This is forward-compatible change to support @vue/compat #1981 (closed)

Does this MR meet the acceptance criteria?

Conformity

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• Added the ~"component:*" label(s) if applicable.