Introducing view field group syncable entity (#17867)

## Context
Introduces a new viewFieldGroup entity that allows grouping view fields
into sections (e.g. "General", "Additional", "Other") within a view.

The page layout fields widget needs a way to organize fields into
sections. Today, views have no concept of field grouping. This PR
introduces the viewFieldGroup entity which sits between a view and its
viewFields, enabling section-based organization.

<img width="401" height="724" alt="Layout - V2 (customize visibility)"
src="https://github.com/user-attachments/assets/6376e2ab-44db-42bf-9d2c-758f56f6b548"
/>

---------

Co-authored-by: Charles Bochet <charles@twenty.com>

packages/twenty-front/src/modules/metadata-error-handler/hooks/useMetadataErrorHandler.ts

@@ -25,6 +25,7 @@ export const useMetadataErrorHandler = () => {
     fieldMetadata: t`field`,
     view: t`view`,
     viewField: t`view field`,
+    viewFieldGroup: t`view field group`,
     viewGroup: t`view group`,
     viewFilter: t`view filter`,
     index: t`index`,