Replace weekly_hours_worked with weekly_hours_worked_before_lsr in SNAP formula

[DTrim99]

#4975 introduced a circular calculation error for simulations involving labor supply responses:

1. weekly_hours_worked depends on labor_supply_behavioral_response
2. labor_supply_behavioral_response depends on income changes
3. Income changes depend on benefits like SNAP
4. SNAP calculations now depend on snap_unit_size (introduced in Exclude students from the SNAP unit with certain exceptions.  #4975)
5. snap_unit_size depends on is_snap_ineligible_student
6. is_snap_ineligible_student depends on weekly_hours_worked

To avoid this, let's change the is_snap_ineligible_student formula to use weekly_hours_worked_before_lsr instead of weekly_hours_worked.