chore(*): remove unused code (#6781)

The code removed in the PR was flagged as unused by the JetBrains
inspector.

I did a QA on the dev environment but other checks are highly
recommended.

There is one commit by scope to make the review easier.

---------

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

packages/twenty-server/src/engine/metadata-modules/field-metadata/validators/is-field-metadata-options.validator.ts

@@ -52,12 +52,4 @@ export class IsFieldMetadataOptions {
       return false;
     }
   }
-
-  defaultMessage(): string {
-    if (this.validationErrors.length > 0) {
-      return this.validationErrors.join(', ');
-    }
-
-    return 'FieldMetadataOptions is not valid';
-  }
 }