ACP2E-1916: Unable to sort catalog by Custom Attribute of type Dropdown

- with test

Author: arnobsh

app/code/Magento/Elasticsearch/Model/Adapter/BatchDataMapper/ProductDataMapper.php

@@ -250,6 +250,7 @@ private function convertAttribute(Attribute $attribute, array $attributeValues,
      * - "Visible in Advanced Search" (is_visible_in_advanced_search)
      * - "Use in Layered Navigation" (is_filterable)
      * - "Use in Search Results Layered Navigation" (is_filterable_in_search)
+     * - "Use in Sorting in Product Listing" (used_for_sort_by)
      *
      * @param Attribute $attribute
      * @return bool
@@ -261,6 +262,7 @@ private function isAttributeLabelsShouldBeMapped(Attribute $attribute): bool
             || $attribute->getIsVisibleInAdvancedSearch()
             || $attribute->getIsFilterable()
             || $attribute->getIsFilterableInSearch()
+            || $attribute->getUsedForSortBy()
         );
     }
 

app/code/Magento/Elasticsearch/Test/Unit/Model/Adapter/BatchDataMapper/ProductDataMapperTest.php

@@ -373,6 +373,57 @@ public static function mapProvider(): array
                 [10 => '44', 11 => '45'],
                 ['color' => [44, 45], 'color_value' => ['red', 'black']],
             ],
+            'select with options with sort by and filterable' => [
+                10,
+                [
+                    'attribute_code' => 'color',
+                    'backend_type' => 'text',
+                    'frontend_input' => 'select',
+                    'is_searchable' => true,
+                    'used_for_sort_by' => true,
+                    'is_filterable_in_grid' => true,
+                    'options' => [
+                        ['value' => '44', 'label' => 'red'],
+                        ['value' => '45', 'label' => 'black'],
+                    ],
+                ],
+                [10 => '44', 11 => '45'],
+                ['color' => [44, 45], 'color_value' => ['red', 'black']],
+            ],
+            'unsearchable select with options with sort by and filterable' => [
+                10,
+                [
+                    'attribute_code' => 'color',
+                    'backend_type' => 'text',
+                    'frontend_input' => 'select',
+                    'is_searchable' => false,
+                    'used_for_sort_by' => false,
+                    'is_filterable_in_grid' => false,
+                    'options' => [
+                        ['value' => '44', 'label' => 'red'],
+                        ['value' => '45', 'label' => 'black'],
+                    ],
+                ],
+                '44',
+                ['color' => 44],
+            ],
+            'select with options with sort by only' => [
+                10,
+                [
+                    'attribute_code' => 'color',
+                    'backend_type' => 'text',
+                    'frontend_input' => 'select',
+                    'is_searchable' => false,
+                    'used_for_sort_by' => true,
+                    'is_filterable_in_grid' => false,
+                    'options' => [
+                        ['value' => '44', 'label' => 'red'],
+                        ['value' => '45', 'label' => 'black'],
+                    ],
+                ],
+                [10 => '44', 11 => '45'],
+                ['color' => [44, 45], 'color_value' => ['red', 'black']],
+            ],
             'multiselect without options' => [
                 10,
                 [