refactor(tests): separate handler/listener tests and remove setTimeout hacks

refactor(tests): separate handler/listener tests and remove setTimeout hacks

Align TriggerMessage, UpdateFirmware, and GetLog test files with the
RequestStopTransaction reference pattern:
- Split into 'Handler validation' + 'event listener' describe groups
- Replace raw setTimeout delays with withMockTimers where needed
- Use emit() directly for listener tests (no wrapper helpers)
- Follows TEST_STYLE_GUIDE.md conventions