Fix: failures on uncaught exception (should use Cypress.env, not process.env)

[YakovL]

Motivation and context

This is a follow up to #831: I've stumbled upon another issue that reproducibly produced the process is not defined error, applied my suggestion from comments and confirmed that the bug goes away indeed (process is not defined is no longer shown, the step passes).

Quality checklist

• I have performed a self-review of my code.

Todo

• Find whether there's a e2e test for this feature, check if it was red before and got green now

[r3kt-eth]

thank you for this fix 🙏

[YakovL]

@r3kt-eth thanks for merging! Please take a look at #828, too