Fix ObjectType casing and conflict between Relation and RelationMetadata (#9849)

Fixes #9827 

Also uncovered a conflict with `@objectType('Relation')` and
`@objectType('relation)`

I don't want to address it in this PR so I will create a followup issue
when we close this but I think there's a confusion between
Relation/RelationMetadata, it's unclear what is what

---------

Co-authored-by: Antoine Moreaux <moreaux.antoine@gmail.com>

packages/twenty-server/src/engine/core-modules/user/dtos/workspace-member.dto.ts

@@ -8,7 +8,7 @@ import {
   WorkspaceMemberTimeFormatEnum,
 } from 'src/modules/workspace-member/standard-objects/workspace-member.workspace-entity';
 
-@ObjectType('FullName')
+@ObjectType()
 export class FullName {
   @Field({ nullable: false })
   firstName: string;
@@ -17,7 +17,7 @@ export class FullName {
   lastName: string;
 }
 
-@ObjectType('WorkspaceMember')
+@ObjectType()
 export class WorkspaceMember {
   @IDField(() => UUIDScalarType)
   id: string;

packages/twenty-server/src/engine/core-modules/user/user.entity.ts

@@ -27,7 +27,7 @@ registerEnumType(OnboardingStatus, {
 });
 
 @Entity({ name: 'user', schema: 'core' })
-@ObjectType('User')
+@ObjectType()
 @Index('UQ_USER_EMAIL', ['email'], {
   unique: true,
   where: '"deletedAt" IS NULL',