Remove old relations (#11993)

This is a first PR to remove old relation logic

Next steps:
- remove relationMetadata from cache
- remove relationMetadata table content and structure
- refactor relationDefinition to leverage field.settings instead

packages/twenty-server/src/engine/api/graphql/graphql-query-runner/interfaces/base-resolver-service.ts

@@ -138,7 +138,6 @@ export abstract class GraphqlQueryBaseResolverService<
         objectMetadataItemWithFieldMaps.fieldsByName,
         objectMetadataItemWithFieldMaps.fieldsByJoinColumnName,
         options.objectMetadataMaps,
-        featureFlagsMap,
       );
 
       const selectedFields = graphqlFields(options.info);
@@ -170,7 +169,6 @@ export abstract class GraphqlQueryBaseResolverService<
         objectMetadataItemWithFieldMaps,
         authContext.workspace.id,
         options.objectMetadataMaps,
-        featureFlagsMap[FeatureFlagKey.IsNewRelationEnabled],
       );
 
       const resultWithGettersArray = Array.isArray(resultWithGetters)