funnel chart handle duplicated steps (#45333)

...e_laptop_static_viz_FunnelChart_With_Duplicated_Steps.png

.loki/reference/chrome_laptop_viz_Funnel_Default.png

...static-viz/components/FunnelChart/FunnelChart.stories.tsx

...etabase/static-viz/components/FunnelChart/FunnelChart.tsx

...etabase/static-viz/components/FunnelChart/stories-data.ts

...etabase/static-viz/components/FunnelChart/utils/funnel.ts

...etabase/visualizations/echarts/cartesian/model/dataset.ts

...sualizations/echarts/cartesian/model/dataset.unit.spec.ts

frontend/src/metabase/visualizations/lib/dataset.ts

...tend/src/metabase/visualizations/lib/dataset.unit.spec.ts

frontend/src/metabase/visualizations/shared/utils/data.ts

...e/visualizations/visualizations/Funnel/Funnel.stories.tsx

.../metabase/visualizations/visualizations/Funnel/Funnel.tsx

...rc/metabase/visualizations/visualizations/Funnel/types.ts

...se/visualizations/visualizations/RowChart/utils/events.ts