feat: add Relation field form (#2572)

* feat: add useCreateOneRelationMetadata and useRelationMetadata

Closes #2423

* feat: add Relation field form

Closes #2003

---------

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

front/src/modules/settings/data-model/hooks/useFieldPreview.ts

@@ -0,0 +1,40 @@
+import { useObjectMetadataItemForSettings } from '@/object-metadata/hooks/useObjectMetadataItemForSettings';
+import { useFindManyObjectRecords } from '@/object-record/hooks/useFindManyObjectRecords';
+import { useLazyLoadIcon } from '@/ui/input/hooks/useLazyLoadIcon';
+import { Field } from '~/generated-metadata/graphql';
+import { assertNotNull } from '~/utils/assert';
+
+export const useFieldPreview = ({
+  fieldMetadata,
+  objectMetadataId,
+}: {
+  fieldMetadata: Partial<Pick<Field, 'icon' | 'id' | 'type'>>;
+  objectMetadataId: string;
+}) => {
+  const { findObjectMetadataItemById } = useObjectMetadataItemForSettings();
+  const objectMetadataItem = findObjectMetadataItemById(objectMetadataId);
+
+  const { objects } = useFindManyObjectRecords({
+    objectNamePlural: objectMetadataItem?.namePlural,
+    skip: !objectMetadataItem || !fieldMetadata.id,
+  });
+
+  const { Icon: ObjectIcon } = useLazyLoadIcon(objectMetadataItem?.icon ?? '');
+  const { Icon: FieldIcon } = useLazyLoadIcon(fieldMetadata.icon ?? '');
+
+  const [firstRecord] = objects;
+  const fieldName = fieldMetadata.id
+    ? objectMetadataItem?.fields.find(({ id }) => id === fieldMetadata.id)?.name
+    : undefined;
+  const value = fieldName ? firstRecord?.[fieldName] : undefined;
+
+  return {
+    entityId: firstRecord?.id || `${objectMetadataId}-no-records`,
+    FieldIcon,
+    fieldName: fieldName || `${fieldMetadata.type}-new-field`,
+    hasValue: assertNotNull(value),
+    ObjectIcon,
+    objectMetadataItem,
+    value,
+  };
+};