Draft: Add `emits` check to frontend test suite

What does this MR do?

👷 🚧 Demo for RFC

This MR demonstrates how we could declare emits on our components and how just a tiny monkey-patch to Vue prototype can help us in gaining confidence in our test suite

Pipeline failure is intended. Discovered tests are fixed in !40449 (merged)

Screenshots

N/A

Does this MR meet the acceptance criteria?

Conformity

Not intended for merge