Deprecate FieldMetadataInterface (#13264)

# Introduction

From the moment replaced the FieldMetadataInterface definition to:
```ts
import { FieldMetadataType } from 'twenty-shared/types';

import { FieldMetadataEntity } from 'src/engine/metadata-modules/field-metadata/field-metadata.entity';

export type FieldMetadataInterface<
  T extends FieldMetadataType = FieldMetadataType,
> = FieldMetadataEntity<T>;
```
After this PR merge will create a new one removing the type and
replacing it to `FieldMetadataEntity`.
Did not renamed it here to avoid conflicts on naming + type issues fixs
within the same PR

## Field metadata entity RELATION or MORPH
Relations fields cannot be null for those field metadata entity instance
anymore, but are never for the others see
`packages/twenty-server/src/engine/metadata-modules/field-metadata/types/field-metadata-entity-test.type.ts`
( introduced TypeScript tests )

## Concerns
- TS_VECTOR is the most at risk with the `generatedType` and
`asExpression` removal from interface

## What's next
- `FielMetadataInterface` removal and rename ( see introduction )
- Depcrecating `ObjectMetadataInterface`
- Refactor `FieldMetadataEntity` optional fiels to be nullable only
- TO DIG `never` occurences on settings, defaultValue etc
- Some interfaces will be replaced by the `FlatFieldMetadata` when
deprecating the current sync and comparators tools

packages/twenty-server/test/integration/metadata/suites/object-metadata/utils/create-relation-between-objects.util.ts

@@ -4,6 +4,9 @@ import { FieldMetadataType } from 'twenty-shared/types';
 
 import { RelationType } from 'src/engine/metadata-modules/field-metadata/interfaces/relation-type.interface';
 
+import { FieldMetadataDTO } from 'src/engine/metadata-modules/field-metadata/dtos/field-metadata.dto';
+import { RelationDTO } from 'src/engine/metadata-modules/field-metadata/dtos/relation.dto';
+
 export const createRelationBetweenObjects = async <
   T extends FieldMetadataType.RELATION | FieldMetadataType.MORPH_RELATION,
 >({
@@ -41,22 +44,35 @@ export const createRelationBetweenObjects = async <
     },
   };
 
-  const {
-    data: { createOneField: createdFieldPerson },
-  } = await createOneFieldMetadata<typeof type>({
+  const { data } = await createOneFieldMetadata<typeof type>({
     input: createFieldInput,
     gqlFields: `
             id
             name
             label
             isLabelSyncedWithName
+            settings
             relation {
               type
+              sourceObjectMetadata {
+                id
+                nameSingular
+                namePlural
+              }
+              targetObjectMetadata {
+                id
+                nameSingular
+                namePlural
+              }
+              sourceFieldMetadata {
+                id
+                name
+              }
               targetFieldMetadata {
                 id
+                name
               }
             }
-            settings
             object {
               id
               nameSingular
@@ -65,5 +81,7 @@ export const createRelationBetweenObjects = async <
     expectToFail: false,
   });
 
-  return createdFieldPerson;
+  return data.createOneField as unknown as FieldMetadataDTO<T> & {
+    relation: RelationDTO;
+  };
 };