fix(server): Correctly mark non-nullable GraphQL fields in entities

server/src/entity/product-option/product-option.graphql

@@ -3,7 +3,7 @@ type ProductOption implements Node {
     languageCode: LanguageCode
     code: String
     name: String
-    translations: [ProductOptionTranslation]
+    translations: [ProductOptionTranslation!]!
 }
 
 type ProductOptionTranslation {

server/src/entity/product-variant/product-variant.graphql

@@ -5,8 +5,8 @@ type ProductVariant implements Node {
     name: String
     image: String
     price: Int
-    options: [ProductOption]
-    translations: [ProductVariantTranslation]
+    options: [ProductOption!]!
+    translations: [ProductVariantTranslation!]!
 }
 
 type ProductVariantTranslation {

server/src/entity/product/product.graphql

@@ -5,9 +5,9 @@ type Product implements Node {
     slug: String
     description: String
     image: String
-    variants: [ProductVariant]
-    optionGroups: [ProductOptionGroup]
-    translations: [ProductTranslation]
+    variants: [ProductVariant!]!
+    optionGroups: [ProductOptionGroup!]!
+    translations: [ProductTranslation!]!
 }
 
 type ProductTranslation {