Morph relation validation v2 (#14141)

## Introduction
Binding morph relation validation to relation validation code flow
Please note that ALL create field will go through basic atomic
validation, which involve name availability and so on

close https://github.com/twentyhq/core-team-issues/issues/1407

packages/twenty-server/src/engine/metadata-modules/flat-field-metadata/utils/from-morph-relation-create-field-input-to-flat-field-metadatas.util.ts

@@ -35,8 +35,7 @@ export const fromMorphRelationCreateFieldInputToFlatFieldMetadatas = async ({
 
   if (
     !isDefined(rawMorphCreationPayload) ||
-    !Array.isArray(rawMorphCreationPayload) ||
-    rawMorphCreationPayload.length === 0
+    !Array.isArray(rawMorphCreationPayload)
   ) {
     return {
       status: 'fail',

packages/twenty-server/src/engine/metadata-modules/flat-field-metadata/utils/is-enum-validate-one-field-metadata-args.util.ts

@@ -1,13 +0,0 @@
-import {
-  type EnumFieldMetadataType,
-  type FieldMetadataType,
-} from 'twenty-shared/types';
-
-import { isEnumFieldMetadataType } from 'src/engine/metadata-modules/field-metadata/utils/is-enum-field-metadata-type.util';
-import { type ValidateOneFieldMetadataArgs } from 'src/engine/metadata-modules/flat-field-metadata/services/flat-field-metadata-validator.service';
-
-export const isEnumValidateOneFieldMetadata = <T extends FieldMetadataType>(
-  args: ValidateOneFieldMetadataArgs<T>,
-): args is ValidateOneFieldMetadataArgs<T> &
-  ValidateOneFieldMetadataArgs<EnumFieldMetadataType> =>
-  isEnumFieldMetadataType(args.flatFieldMetadataToValidate.type);