Refactor morph field name and morph data loader (#14299)

# Introduction
Storing morph relation field names directly in database, using morphId
to aggregate them
Removing dynamic morph field metadata computation in schemas and data
loader

Will add integration tests on morph data loader entry

closes https://github.com/twentyhq/core-team-issues/issues/1425 
closes https://github.com/twentyhq/core-team-issues/issues/1424 
closes https://github.com/twentyhq/core-team-issues/issues/1423

packages/twenty-server/src/engine/workspace-manager/dev-seeder/metadata/custom-fields/constants/pet-custom-relation-field-seeds.constant.ts

@@ -20,4 +20,19 @@ export const PET_CUSTOM_RELATION_FIELD_SEEDS: (FieldMetadataSeed & {
     ],
     targetObjectMetadataNames: ['surveyResult', 'rocket'],
   },
+  {
+    type: FieldMetadataType.MORPH_RELATION,
+    label: 'Helper of the Pet (rocket or survey)',
+    name: 'helper',
+    icon: 'IconRelationOneToMany',
+    morphRelationsCreationPayload: [
+      {
+        type: RelationType.ONE_TO_MANY,
+        targetObjectMetadataId: 'to-be-resolved-later',
+        targetFieldLabel: 'Helped by',
+        targetFieldIcon: 'IconRelationOneToMany',
+      },
+    ],
+    targetObjectMetadataNames: ['surveyResult', 'rocket'],
+  },
 ];