Defining unknown properties as exist properties is wrong

Version

2.7.8

Reproduction link

Steps to reproduce

This issue was created first in Vetur & later fixed in @vuejs/composition-api as below https://github.com/vuejs/vetur/issues/2505
https://github.com/vuejs/composition-api/issues/609

Recently the same issue is created in Volar and closed mentioning common.ts definitions in vuejs/composition-api https://github.com/johnsoncodehk/volar/issues/1350

What is expected?

Error has to be displayed when unknown property or data in template (typescript code)

What is actually happening?

No error is displayed when unknown property or data in template (typescript code) due to export type Data = { [key: string]: unknown } in types/common.d.ts