refac: removed ugly multi-line method chaining

internal/infrastructure/persistence/repositories/imageRepository.go

@@ -123,11 +123,12 @@ func (i ImageRepository) ListByStoredNames(storedNames []string) ([]domain.Image
 }
 
 func (i ImageRepository) duplicatedHashes() *gorm.DB {
-	return i.db.Model(&entity.Image{}).
-		Select("sha256").
-		Where("sha256 <> ''").
-		Group("sha256").
-		Having("COUNT(*) > 1")
+	query := i.db.Model(&entity.Image{})
+	query = query.Select("sha256")
+	query = query.Where("sha256 <> ''")
+	query = query.Group("sha256")
+	query = query.Having("COUNT(*) > 1")
+	return query
 }
 
 func imagesToDomain(models []entity.Image) []domain.Image {