[Requires "warm" cache flush (no immediate downtime before flush)] Migrate viewGroup.fieldMetadataId -> view.mainGroupByFieldMetadataId (1/3) (#16206)

In this PR (1/3)
- introduce view.mainGroupByFieldMetadataId as the new reference
determining which fieldMetadataId is used in a grouped view, in order to
deprecate viewGroup.fieldMetadataId which creates inconsistencies.
view.mainGroupByFieldMetadataId is now filled at every view creation,
though not in use yet.
- Introduce a command to backfill view.mainGroupByFieldMetadataId for
existing views + delete all viewGroup.fieldMetadataId with a
fieldMetadataId that is not view.mainGroupByFieldMetadataId. (It should
concern 37 active workspaces)
- Temporarily disable the option to change a grouped view's
fieldMetadataId as for now it creates inconsistencies. This feature can
be reintroduced when we have done the full migration.

In a next PR
- (2/3) use view.mainGroupByFieldMetadataId instead of
viewGroup.fieldMetadataId. In FE we may keep viewGroup.fieldMetadataId
as a state (TBD). View groups will now be created / deleted as a side
effect of view's mainGroupByFieldMetadataId update.
- (3/3) remove viewGroup.fieldMetadataId

---------

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

packages/twenty-front/src/testing/mock-data/views.ts

@@ -28,7 +28,6 @@ export const mockedViewsData: View[] = [
     type: ViewType.Table,
     icon: 'IconSkyline',
     key: ViewKey.Index,
-    kanbanFieldMetadataId: '',
     kanbanAggregateOperation: AggregateOperations.COUNT,
     kanbanAggregateOperationFieldMetadataId: '',
     position: 0,
@@ -49,7 +48,6 @@ export const mockedViewsData: View[] = [
     type: ViewType.Table,
     icon: 'IconPerson',
     key: ViewKey.Index,
-    kanbanFieldMetadataId: '',
     kanbanAggregateOperation: AggregateOperations.COUNT,
     kanbanAggregateOperationFieldMetadataId: '',
     position: 0,
@@ -70,7 +68,6 @@ export const mockedViewsData: View[] = [
     type: ViewType.Kanban,
     icon: 'IconOpportunity',
     key: ViewKey.Index,
-    kanbanFieldMetadataId: '',
     kanbanAggregateOperation: AggregateOperations.COUNT,
     kanbanAggregateOperationFieldMetadataId: '',
     position: 0,
@@ -91,7 +88,6 @@ export const mockedViewsData: View[] = [
     type: ViewType.Table,
     icon: 'IconSkyline',
     key: null,
-    kanbanFieldMetadataId: '',
     kanbanAggregateOperation: AggregateOperations.COUNT,
     kanbanAggregateOperationFieldMetadataId: '',
     position: 0,