Fix Tests workflow regressions from safety-data junction schema changes

[Copilot]

The Tests GitHub Actions job was failing after safety-data schema changes removed non_urban_intersection from marker views while related widget filtering still depended on it. The same branch also left a few tests pinned to pre-migration severity IDs and vehicle mappings.

• Junction filtering

  • Update road-segment junction expansion to use the current marker view shape:
    • prefer non_urban_intersection when present,
    • fall back to intersection,
    • return false() when the view has no junction field or the segment has no mapped junctions.
  • This prevents widget queries from raising attribute errors on updated marker views.

• Severity filter compatibility

  • Replace hardcoded injured severity IDs in widget filter construction with InjurySeverity.codes().
  • Keeps query filters aligned with the new CBS-backed severity values.

• Targeted test updates

  • Update enum-backed test fixtures to use current AccidentSeverity values.
  • Refresh involved-query expectations for the new safety-data mappings and sample records.
  • Add coverage for the new intersection fallback and the false() behavior when junction expansion is unavailable.

def get_expression_for_segment_junctions(segment_id: int, table_obj):
    sg = SegmentJunctions.get_instance()
    junctions = sg.get_segment_junctions(segment_id)
    if not junctions:
        return false()
    if hasattr(table_obj, "non_urban_intersection"):
        field = getattr(table_obj, "non_urban_intersection")
    elif hasattr(table_obj, "intersection"):
        field = getattr(table_obj, "intersection")
    else:
        return false()
    return field.in_(junctions)