Complete Jest AE v3 and bring it to stable

[IlCallo]

Jest AE v3 is still in alpha and have many problems
It's generally less suited for component testing when compared to Cypress or Playwright, but many people keep using it nonetheless, so we should at least ensure it works for basic tests

We need to upgrade its deps as we're still on an early version of vue-jest and VTU, but we need to stick to Jest 26 for v3, as Jest 27 have many breaking changes

We should also add some more smoke tests to catch possible edge cases #240

Once we do these things we can release the beta version

[IlCallo]

Due to the many improvements in new Jest versions, we'll bump Jest version while moving from alpha to beta phase
People will have to upgrade from Jest 26 to Jest 29