Split bar graph into two distinct horizontal and vertical bars (#15061)

### Summary

Split BAR into VERTICAL_BAR and HORIZONTAL_BAR as separate chart types.

### The Problem

Initially wanted a simple vertical/horizontal toggle for bar charts, but
ran into a GraphQL union type
constraint: union types can't have the same field name with different
nullability.

- Vertical bars need groupByFieldMetadataIdX as required (categories on
X)
- Horizontal bars need groupByFieldMetadataIdY as required (categories
on Y)
  - GraphQL schema generation fails with this setup

### The Solution

Use semantic primaryAxis and secondaryAxis naming that's
orientation-agnostic:

- primaryAxisGroupByFieldMetadataId = main grouping field (e.g.,
"Company Name")
- secondaryAxisGroupByFieldMetadataId = optional secondary grouping
(e.g., "Stage")

These fields have consistent meaning regardless of orientation. The
visual mapping happens at the UI layer:
  - Vertical bars: primary data renders on X-axis, secondary on Y-axis
  - Horizontal bars: primary data renders on Y-axis, secondary on X-axis

Both chart types share the same DTO structure with consistent
nullability.

### What Changed

  - Split GraphType.BAR → VERTICAL_BAR | HORIZONTAL_BAR
- Renamed fields: primaryAxisGroupByFieldMetadataId,
secondaryAxisGroupByFieldMetadataId (+ subfield
  variants)
- useChartSettingsValues(): Maps semantic fields to setting values (no
swapping)
- getBarChartSettings(): Dynamically arranges settings panel based on
orientation
- transformGroupByDataToBarChartData(): Maps semantic fields to Nivo's
layout prop
  
  video QA
  

https://github.com/user-attachments/assets/479061b5-712e-4ca6-9858-95273d1f16c1

packages/twenty-front/src/modules/page-layout/widgets/graph/components/GraphWidget.tsx

@@ -100,7 +100,8 @@ export const GraphWidget = ({
         </Suspense>
       );
 
-    case GraphType.BAR:
+    case GraphType.VERTICAL_BAR:
+    case GraphType.HORIZONTAL_BAR:
       return <GraphWidgetBarChartRenderer widget={widget} />;
 
     case GraphType.LINE: