fix(jest): preserve custom environment handleTestEvent

[formaceft-93]

This fixes createJestEnvironment overwriting handleTestEvent from custom Jest environments. That broke integrations such as jest-environment-puppeteer, where users rely on handleTestEvent to react to Circus events, for example taking screenshots on test_fn_failure.

The factory now captures any existing environment event handler, calls it first, and then runs Allure’s own event handling. Sync handlers, async handlers, and thrown/rejected errors are all preserved: Allure still processes the event, and Jest still receives the original failure.

Closes #1289

Checklist

• Sign Allure CLA
• Provide unit tests