[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/generated/graphql.ts

@@ -689,6 +689,7 @@ export type CoreView = {
   kanbanAggregateOperation?: Maybe<AggregateOperations>;
   kanbanAggregateOperationFieldMetadataId?: Maybe<Scalars['UUID']>;
   key?: Maybe<ViewKey>;
+  mainGroupByFieldMetadataId?: Maybe<Scalars['UUID']>;
   name: Scalars['String'];
   objectMetadataId: Scalars['UUID'];
   openRecordIn: ViewOpenRecordIn;
@@ -963,6 +964,7 @@ export type CreateViewInput = {
   kanbanAggregateOperation?: InputMaybe<AggregateOperations>;
   kanbanAggregateOperationFieldMetadataId?: InputMaybe<Scalars['UUID']>;
   key?: InputMaybe<ViewKey>;
+  mainGroupByFieldMetadataId?: InputMaybe<Scalars['UUID']>;
   name: Scalars['String'];
   objectMetadataId: Scalars['UUID'];
   openRecordIn?: InputMaybe<ViewOpenRecordIn>;
@@ -4258,6 +4260,7 @@ export type UpdateViewInput = {
   isCompact?: InputMaybe<Scalars['Boolean']>;
   kanbanAggregateOperation?: InputMaybe<AggregateOperations>;
   kanbanAggregateOperationFieldMetadataId?: InputMaybe<Scalars['UUID']>;
+  mainGroupByFieldMetadataId?: InputMaybe<Scalars['UUID']>;
   name?: InputMaybe<Scalars['String']>;
   openRecordIn?: InputMaybe<ViewOpenRecordIn>;
   position?: InputMaybe<Scalars['Float']>;