B2B-2259: customAttributeMetadata GraphQl query has no cache identity

- WebAPI test CR fixes

Author: rganin

app/code/Magento/EavGraphQl/Plugin/Eav/AttributePlugin.php

@@ -20,7 +20,7 @@ class AttributePlugin
      * @param Attribute $subject
      * @param array $result
      *
-     * @return Attribute
+     * @return string[]
      */
     public function afterGetIdentities(Attribute $subject, array $result): array
     {

dev/tests/api-functional/testsuite/Magento/GraphQl/Eav/CustomAttributesMetadataCacheTest.php

@@ -110,12 +110,13 @@ public function testCacheDifferentStores()
     }
 
     /**
-     * Per-store assertion helper method.
+     * Assert attribute option labels for each store provided.
+     *
+     * @param array $storeOptions
+     * @param string $storeCode
+     * @param \Magento\Store\Api\Data\StoreInterface[] $stores
+     * @param array $options
      *
-     * @param $storeOptions
-     * @param $storeCode
-     * @param $stores
-     * @param $options
      * @return void
      */
     private function assertOptionValuesPerStore($storeOptions, $storeCode, $stores, $options)