fix(jsonapi): emit no empty properties list in attributes

Fixes #8756

Author: soyuka

src/JsonApi/JsonSchema/SchemaFactory.php

@@ -71,7 +71,6 @@ final class SchemaFactory implements SchemaFactoryInterface, SchemaFactoryAwareI
         ],
         'attributes' => [
             'type' => 'object',
-            'properties' => [],
         ],
     ];
 
@@ -350,7 +349,9 @@ private function buildDefinitionPropertiesSchema(string $key, string $documentDe
         }
 
         $replacement = self::PROPERTY_PROPS;
-        $replacement['attributes']['properties'] = $attributes;
+        if ([] !== $attributes) {
+            $replacement['attributes']['properties'] = $attributes;
+        }
 
         $included = [];
         if (\count($relationships) > 0) {

src/JsonApi/Tests/JsonSchema/SchemaFactoryTest.php

@@ -120,7 +120,6 @@ public function testHasRootDefinitionKeyBuildSchema(): void
                     ],
                     'attributes' => [
                         'type' => 'object',
-                        'properties' => [],
                     ],
                 ],
                 'required' => [