Cypress.env() was deprecated and needs to be replaced by either cy.env() or Cypress.expose()

## Describe the bug
The Cypress.env() method was deprecated in version 15.10.0, see https://docs.cypress.io/api/cypress-api/env. It needs to be replaced by either cy.env() or Cypress.expose().
This concerns nearly _all_ existing cypress tests.

## Related work
* #3978
