tests/utils/helpers:

Removed the implicit assumption in `get_risk_job` of job config files
always being in the demos/ folder.

This is also more consistent with `get_hazard_job`.
tests:

Updated usage of `get_risk_job` to fix broken tests.
tests/utils/helpers:

Updated docstring of `get_risk_job`.
tests/engine2_test:

WIP for testing hazard/risk calculation deletion cases.